Original subtitles

Where do we come from?

When did our story really begin?

Who were the first Homo sapiens?

Not just humans who looked like us,

but people who thought and behaved as we do.

People we would recognise as truly one of us.

We, Homo sapiens, first appeared over 300,000 years ago.

We were not the first species of human.

We're not the biggest, we're not the strongest,

we're just the latest in a long line of other humans.

Yet, a few hundred thousand years later, we are the only ones

left, and the most dominant form of life on this planet.

How on earth did this happen?

I'm Ella Al-Shamahi, a paleoanthropologist.

People spend their whole lives trying to find

a fossil as significant as this.

You might think you know the story of human evolution, but now

we are discovering it's stranger and more dramatic than we ever imagined.

This was something that wiped out 13 people in the same family.

Thanks to ground-breaking new science, we are

rewriting the story of our origins.

From our tentative first steps...

..to the migrations that carried us across continents.

And our encounters with other human species we met along the way.

It's small, it's really tiny.

I can see why you would call it the Hobbit.

From the first marks we made on cave walls...

..to the rise of cities...

..these are the unlikely events that forged us.

Moments of chance, but also ingenuity,

of beauty and destruction.

This is us, this is our story, and it's what happened

in the 99% of our history before the invention of writing, when our

story wasn't written in books, but was written in our bones and DNA.

This is the story of how we became...

..human.

This story begins in Africa, in a time long ago...

..in a world before we existed at all.

In many ways, this world would feel familiar...

..teeming with animals we'd recognise.

But there was one crucial difference.

This world was inhabited by not one,

but by many other types of human.

We're used to living in a world filled with other species.

Over eight million share our planet with us.

But there is only one of us, only one human species, Homo sapiens.

And so, it's really easy to forget that it wasn't always like this.

The world before us was alive with other human activity.

Around six million years before Homo sapiens appeared...

..some primates left the trees.

They started walking upright and over time, began using stone tools.

These toolmakers became the earliest form of human.

Over millions of years, these humans continued to evolve...

..forming a diverse family tree of different human species.

Who were these other humans and how are we connected to them?

Well, they're all part of our extended family,

so our parents, grandparents, great-aunts, cousins.

Some were our ancestors, others just relatives.

But all of them were part of our lineage, our family tree,

that spanned millennia.

Around the time Homo sapiens emerged...

..there were at least six different human species.

And using the latest scientific data,

we can reconstruct what they might have looked like.

There were so many species of human.

You had Homo erectus, an ancestor of ours, and an incredibly

successful species, because they lived for about two million years.

Now, Homo erectus was actually the first in our genus to leave Africa.

And we also think that they were the first to use fire.

There's also Homo neanderthalensis,

who you probably know as the Neanderthals.

Neanderthals lived in Europe, all the way into Central Asia.

They were cold-adapted.

And they were expert hunters.

There was also Homo floresiensis,

who some people affectionately call the Hobbit...

..because they were only about a metre tall,

so that's about three and a half feet.

Tiny, and yet adapted for living on an island.

It seems like a fantastical world, and I can't help it,

it reminds me of Lord Of The Rings.

Only, instead of a world with elves and dwarves,

you had a magical place with other humans.

The human family tree had many branches.

But which branch did Homo sapiens first emerge from?

We don't know for sure,

but we're getting closer than ever to finding out.

For the longest time, we thought we knew the origins of our species.

We thought we began 200,000 years ago in East Africa.

But new revelations from out here in Morocco,

from a part of Africa that people weren't really considering,

are forcing us to rethink our very first steps on this planet.

In a remote cave in North West Africa,

a chance discovery uncovered some mysterious human remains.

Someone unexpected was living here...

..thousands of years earlier than we imagined.

This is Jebel Irhoud 1, and it was a complete mystery,

because some of its features are very much like us,

very Homo sapiens, and others are much older, much more primitive.

So, if you look at this individual's face,

its face looks a lot like ours.

The Homo sapiens face is incredibly gracile.

We have incredibly delicate features.

They, kind of, tuck in under our brain case.

If you imagine a prehistoric human,

you kind of always imagine a much, kind of more prognathic,

we say, much more kind of jutting forwards face.

This individual's face is much more tucked under, it's much shorter.

But there are some features that aren't us.

Notice this brow ridge up here, this supraorbital structure.

Now, look at me.

You don't get modern humans walking around today with these

massive things on top of their eyes.

I mean, it would actually be quite terrifying today if we saw that.

Now, the brain case is not us.

You see how round my brain case is?

It's globular, whereas this is almost stretched out.

It's almost like somebody's got my brain case but kind of

stretched the back of it out.

It's almost like straight-on, the face is Homo sapiens,

but from the other angles, it's not us.

These finds posed a mystery.

They were anomalies that didn't fit neatly into the human family tree.

They looked partly like Homo sapiens...

..and partly like an earlier human.

So, the question was, was this a different species,

or could it be an early version of us?

Several decades after the initial discoveries came a breakthrough.

Archaeologists uncovered another 16 fossils...

..all with the same blend of features.

With each new find, the evidence grew.

These were not some other species, but Homo sapiens,

with hints of an earlier ancestor.

But it wasn't until archaeologists were able to more accurately

date the remains that the final piece of the puzzle fell into place.

The archaeologists, using new and improved dating techniques,

were able to give us dates for these fossils, and they tell us

that these individuals lived about 300,000 years ago.

And that is mind-boggling,

because we thought our species was only about 200,000 years old.

What these fossils tell us is that our species, Homo sapiens,

is 100,000 years older than we thought.

We are a third older than we realised.

This fossil went from being enigmatic

and basically a mystery,

to being one of the most important fossils in our whole field.

Thousands of miles from East Africa where we thought we began,

and far older than expected...

..these are the earliest Homo sapiens ever found.

And they have forced us to rethink other finds across Africa...

..which are painting an entirely new picture of our origins,

suggesting that Jebel Irhoud...

..was just one of many emerging populations,

all in the process of taking shape.

It's...

It's a bit like having a peek behind the curtain of evolution.

This is a stage in the journey to becoming us.

I wonder what it would feel like to come face-to-face with

one of the people from Jebel Irhoud?

If we were to look into their eyes...

..into those quite delicate features,

would we see ourselves within them?

The answer is, they were not modern humans like us.

Not yet.

They were an earlier stage in our evolutionary journey,

bridging the gap between us and our ancient human ancestors.

Our emergence was actually slow, and honestly, at the beginning,

we were just not that special.

Now, early iterations of Homo sapiens, like Jebel Irhoud,

were popping up all over Africa.

We once believed in a single origin, a sole cradle of humanity

in East Africa, but our story is far richer and more interesting.

The latest evidence suggests we emerged gradually,

across thousands of miles, and over hundreds of thousands of years...

..appearing bit by bit...

..like a series of sparks...

..igniting across the African continent.

THUNDERCLAP

And yet, Homo sapiens could have easily vanished without trace.

Because just as we were finding our place in the world...

..something threatened to wipe us out altogether.

It's in East Africa's Great Rift Valley that we can trace

the next chapter of our story.

This dynamic landscape holds some of the clearest

evidence of the forces that set our species on a radically new path.

When they say the Great Rift Valley of East Africa is a dramatic

place, they're not kidding.

I mean, look at it.

I can literally hear it bubbling behind me, and it's

the result of a geological process that sees three tectonic plates

tearing away from each other, which results in a dynamic landscape.

And even though this part doesn't look that hospitable,

it has been a home to people for a very long time.

This is one of the most fossil-rich regions in Africa.

Its unusual geology has not only preserved human remains,

but also offers a glimpse into the forces that drove our evolution.

So, within the lakebeds here, if you dig deep, you can

actually extract sediment cores.

Now, one here in Ethiopia was about 280 metres deep,

so that represents over 600,000 years.

And within that sediment, it's a bit like a time machine,

because bits of ancient environment are trapped.

By analysing these sediment layers,

scientists have uncovered a window

into the world some of the earliest

Homo sapiens were living in.

The information from those sediment cores has been

collated into this graph, and when you zoom out, it actually

paints a really interesting picture, because for the first 300,000

years, you see a period of relative climate stability.

But then, at around 275,000 years ago, something shifts,

and we see a period of fluctuations, volatility, between humid

and arid periods, in a way that just wasn't happening before.

Now, East and West Africa are linked in a kind of climate seesaw.

So, when one is humid, the other is arid, and vice versa.

Over thousands of years, wild climate swings engulfed Africa...

..plunging fledgling populations of Homo sapiens...

..into a world of extremes.

Ecosystems were destroyed.

Rivers and lakes swelled...

..cutting people off from one another.

Elsewhere, grasslands turned to desert.

Survival was a battle against relentless change.

I do think that when we look at these zoomed-out graphs,

we sometimes make a vital error.

We forget to zoom back in.

After all, human evolution is about humans.

There are people like you and me experiencing the peaks

and troughs of those graphs.

People who were suddenly facing droughts, or flash floods,

or perhaps the disappearance of a food source.

Entire communities...

..found themselves isolated.

Some populations dwindled.

The ones who couldn't adapt died out.

This struggle for survival could have wiped

Home sapiens out altogether.

But it didn't.

It had the opposite effect.

It drove us forward.

Under pressure, isolated populations learnt new skills.

Those who could adapt and innovate had a better chance of survival.

Then, as the climate changed, groups came back together.

They shared skills and crucially, they interbred...

..passing beneficial traits on to their children.

It was a process that began to change us permanently.

The people who survived emerged stronger than ever.

Today, most of us live in towns and cities...

..and so, the reality of being affected by the climate

as a result of being a nomadic person kind of escapes us.

But you've actually got a really good example here,

with the Afar people.

They are nomadic, and so they get pushed

and pulled around the landscape.

And it would've been very similar with our ancestors,

but actually in a more extreme fashion.

These different groups, as they were moving around,

would've at times met, and when they did,

they would've, of course, shared skills and knowledge and DNA.

It was this mixing of groups that ultimately brought us

closer to becoming the Homo sapiens we are today.

Our origins as a species are so much more complicated and dynamic,

involving not just East Africa, but the whole of the African continent.

Africa was a continent rich in diversity, and climate acted

as a sort of catalyst, blending these various groups together.

And so, we were formed as a result of a mosaic of these

different populations across Africa.

It was our diversity, our resilience in the face of climate change...

..it shaped us, our minds and our bodies,

and transformed us into a new and evolved human.

We all carry an echo of what happened in Africa

at this pivotal moment...

..because what happened then changed us forever.

What began as diverse, scattered populations...

..in the face of adversity came together...

..propelling us to become one stronger, smarter species.

This is a museum that houses some of the most important

fossils in the human story.

And one of those fossils is Herto 1, easily one of the most

significant Homo sapiens fossils that has ever been found.

And that's because this individual is one of the very first

in our lineage that we can describe as an anatomically modern human.

Its physical characteristics

and traits are overwhelmingly similar to those of yours and mine.

And if you look at this individual compared to Jebel Irhoud,

look how rounded it is.

Some people have put forward this intriguing idea that perhaps

the shape of the skull reflects a change in brain organisation.

This process of globularisation has been linked to language skills

and coordination.

And it is really exciting to consider that this

change in shape reflects a really significant shift in the way

that Homo sapiens were starting to think.

These larger, reorganised brains had slowly

but surely opened a gap between Homo sapiens and our ancestors.

But it wasn't only the size

and shape of our brains that set us apart.

One of the lines of evidence for this are actually the teeth.

Now, scientists have discovered that if you look very

closely at the teeth, what you find are very fine lines called

perikymata, that represent about a week in the life of an individual.

So, that means you can count how long an individual has been

alive, a bit like tree rings.

And so, if you look at a Homo erectus individual

and compare it to, say, a Homo sapiens living today,

our species takes an incredibly long time to get to sexual maturity.

From the lines in their teeth, we know that Homo sapiens

children were growing up much more slowly than earlier humans.

The thinking behind it is that we needed a really long time to

learn how to use these brains of ours.

And the longer that you exist in childhood,

the longer you have to learn.

And so, this thing that is a real headache to so many parents

out there today, that our children take so long to become fully

formed, that might actually be a huge key to our success.

Reorganised minds and longer childhoods,

our brains and bodies had evolved.

At last, we were Homo sapiens who physically looked like us.

What you might call, Sapiens 2.0.

It was some of these anatomically modern Homo sapiens that

began to step out into the wider world.

But beyond Africa was already home to other humans.

Neanderthals had spread across Central Asia and Europe.

Other parts of Asia were populated by multiple species,

including Homo erectus.

And there is evidence in the Middle East

of an early group of Homo sapiens...

..who followed in the footsteps of these other human species.

I do love thinking about those huge moments in our history,

like when Homo sapiens first left Africa.

It was a massive achievement, even though

they would've had no idea of the significance of it.

And it's amazing to think that it happened so early on in our story.

But it's in the Levant that I think things get really interesting.

Evidence has been uncovered of a community of Homo sapiens

living in caves, in what is now Israel.

And it's in this place they would

have encountered something unexpected.

There is one mountain called Mount Carmel where one cave,

called Skhul, has been found with Homo sapiens.

And another cave on the same mountain, called Tabun Cave,

has been found with Neanderthal individuals.

And these two peoples were living at the same time.

It is kind of wonderful to think about.

And of course, the Neanderthals were not an African species,

they were used to living outside of Africa,

whereas for us, this was still very, very new.

Two species sharing the same mountain.

We don't know if they interacted.

But we do know that while Neanderthals remained

in the region, all traces of this group of Homo sapiens vanished.

Their bloodline died out completely.

What is most fascinating about these Homo sapiens isn't who

they met, it isn't even what they achieved.

It's that all of these early dispersals failed.

We know from genetic evidence that those Homo sapiens are not

the ones who would go on to ultimately populate the planet.

This failed migration was a stark reminder of our fragility.

These people looked like us, but there was something missing.

Because what really defines our species isn't how we look.

It's not even the size of our brains.

It's something else altogether.

While these early migrants vanished...

..populations in Africa thrived...

..displaying that special essence that makes us who we are.

A way of thinking and behaving that would set Homo sapiens apart.

And some of the earliest traces of it can be found in this

remote cave in Botswana.

- This is a very large natural outcrop.

And as you can see, it goes on and on.

It's seven metres long.

The front has a natural slit for a mouth,

and a natural depression for an eye.

And even if you want to go that far, a nostril up at the front.

- Right. - With the head rearing up, it does,

in modern eyes, look like a snake.

The overall form has been altered

to make it look even more snake-like.

There are over 300 indentations that have been ground into the

surface over what is obviously an extended period of time.

When the initial excavations were conducted,

they absolutely revealed a number of questions.

One of the things found was an extremely large

number of tools that appeared to be manufactured

and then just left there in pristine condition.

- These look gorgeous. I mean, they absolutely look stunning.

- Once they were manufactured, then you did one of three things with it.

You either manufactured it perfectly and just left it.

- Mh-hm. - Or more interestingly, you burnt it.

But not burnt to just, like, throwing it in a bonfire.

It's controlled burning.

And the third and most bizarre thing that they did with them

is they made it, manufactured it perfectly,

and when they were finished, turned it over, smashed it in the middle.

- These are offerings, aren't they? - Yeah.

The only thing that makes sense, the on... The best fit

is that they're sacrifices, they're offerings.

They're not doing it for fun.

They feel that coming up and doing this act would satisfy some

kind of a need, some kind of, um, a wish, some kind of a desire.

Although it's absolutely magnificent during the daytime...

..it comes to life at night.

- We can't speak to these people, but this...

..this whole place, it gets us

so much closer to what they were thinking, what was going on inside.

- Yeah. We had always had the impression that this type of

abstract thinking would've been beyond the ancestors at that time,

and now we definitely have evidence that that was absolutely wrong,

that they obviously had the ability to hold abstract thought.

You make an offering and hope for something back.

- Asking for probably some of the things that we would ask for -

food, health, children, etc, etc - and you just think,

"Oh, my gosh, that's some of the... That's some of the earliest

"behaviour that we know so well."

Some believe the people who performed these rituals must

have been holding abstract ideas in their heads...

..imagining things they couldn't see.

A clue their minds were sparking and forming connections in a new way.

When I see this, this is what moves me,

because this is who we are, in a way

that feels more us than bones.

See, it is so familiar to us.

We know this behaviour. This is ritual.

Whether it is religion and spirituality, or things

like the handshake, or birthdays, graduation ceremonies, Burning Man,

Glastonbury, New Year's Eve, we are, as a species, obsessed with ritual.

It is profoundly and fundamentally Homo sapiens behaviour.

It's us. We know it.

It was as if they were able to see beyond the tangible.

They were thinking beyond what was just in front of them.

They were venturing into the unknown and into the unseen.

Behaviour like this marked a new chapter in our species' story.

Our minds were awakening, opening up to a world of possibility.

This wasn't confined to ritual.

It touched every part of our lives.

Around 70,000 years ago,

new weapons began appearing across Southern Africa.

Homo sapiens were using abstract thought to innovate.

Inventing complex projectile weapons, like the bow and arrow.

We were seeing the world not just as it was, but as it could be.

It takes a lot to see the potential in a piece of wood.

Projectile weapons were revolutionary technology for us

humans, because up until now, we'd been using close-range

hunting strategies, which were less effective, less lethal,

and yet more dangerous for the person holding the weapon.

For over two million years, early humans mostly relied on axes

and spears.

But Homo sapiens imagined unseen forces like the power

held in wood and string.

Creating something entirely new.

If you look at this bow and arrow, you can

see how much knowledge is required.

You need to know where to get the wood for the bow, you need to

know about the glue, you need to know how taut the string should be.

So many elements that require, not just knowledge,

but the ability to pass that knowledge on.

Something like this is not the result of one person's genius.

It's the result of many, many people, over many generations,

inventing, reinventing, perfecting, tinkering.

We weren't just inventing.

We were adapting and expanding our knowledge.

Human culture was becoming more complex,

that technology was exploding.

Now, many of us think that this is a result of something called

cumulative culture, the idea that you accumulate culture, so every

generation builds upon the previous generation's science and technology.

With cumulative culture, Homo sapiens were becoming

collectively smarter with every generation.

And as our numbers increased, this was more powerful than any weapon.

A giant leap towards becoming the species we are today.

When was our species truly born?

Was it when we first appeared?

Or when we started to look like modern humans?

Or was it when our minds lit up?

Creating, inventing, and building on our knowledge.

Each was a crucial step in our evolution.

But none would be possible without one special ingredient.

The glue that binds all of our achievements together.

It leaves no direct fossil evidence,

but we can find traces of it in some unexpected places.

In archaeology, sometimes the smallest finds actually tell

the grandest of stories.

These are tiny marine shells,

and shells like this have been found in caves in South Africa,

and they are just too small to have been collected for meat.

If you look really closely, what you see is that they have holes in them.

Now, some of these were collected because they already had holes,

but others were perforated by Homo sapiens.

And really close examination of the shells in these caves show that they

had wear marks on them consistent with having been worn on the body.

So, that, along with these holes in them, well, it's really easy to

paint a picture of them having been strung...

..and turned into jewellery.

These weren't just beads, they were emblems.

Symbols of value and meaning...

..shared and understood by everyone.

They've been found with pigment on them,

and it's always the same-coloured pigment, it's red ochre.

Even though ochre comes in yellow, black and red, it's always red.

Perhaps you were trading them for food, for goods,

perhaps you'd give them as some kind of a gift at a wedding,

perhaps they were just a sign of friendliness.

And you can also imagine that people would be wearing them

to make themselves look good, it would perhaps be a sign of prestige.

The making and sharing of these beads was one more

sign our species had made another revolutionary leap.

The ability to pass on knowledge and technology,

sharing rituals and traditions.

All these things suggest Homo sapiens were passing

sophisticated ideas from one mind to another.

Our species had unlocked the power of complex language.

The most remarkable thing about these shells is that they

have been found not just in South Africa, but all over Africa,

from the south, all the way to the north, in Morocco and Algeria.

Not just along the coasts, but all the way inland.

And that, for me, is so exciting,

because when you look at this,

you might think, "Oh, my God, isn't that amazing?

"Humans have a kind of cultural expression

"that they never had before."

While earlier humans probably had basic language...

..it's thought Homo sapiens were speaking to each other

in a more complex way.

Weaving a shared culture.

And forging an invisible bond that united our species

across the entire continent.

All over Africa, we understood the cultural symbolism

of these beads.

Somebody was telling you, "This shell is important, not that shell.

"Red is important, not the other colours."

We had an understanding that wasn't just you, me,

and our three families, you, me, and the village next-door.

We had a kind of symbolism and understanding

and interconnectedness that was continent-wide.

This has never happened before.

For me, this is the birth of our species.

Our species' birth wasn't a single moment.

It unfolded over millennia.

Complex language and our powerful shared culture finally set us

apart from humans before us.

We had become one connected, cooperative species.

We had become Homo sapiens...

..the ancestors of us all.

Sometimes in life, things come together,

and this was a coming together for our species.

It was a perfect storm.

You had a change in brain, you had language, increased numbers,

increased connectivity, cumulative culture, better technology

and weaponry, and the right climate.

But through all of this, there is a hidden thread.

Our secret weapon is that we are a social, cooperative species.

Friendliness, it turns out, is our superpower.

We are more than the sum of our parts.

Whether it's ritual, technology, language,

all of it comes down to cooperation, in my opinion.

And that's how you go from a species that started off feebly,

unremarkably, to one that would

become so extraordinary,

one ready to explore this planet.

..we follow our ancestors as they spread beyond Africa,

taking on extreme environments no others could master...

..travelling beyond the realm of another extraordinary

species of human - the Hobbit.

And eventually, even reaching the distant land of Australia.

Over 300,000 years ago,

Africa was the cradle of humanity -

the place where humans evolved,

including the first of a new species...

..Homo sapiens...

..our species.

From humble beginnings, our growing culture

and connections helped us spread across that great continent.

And then we ventured outwards,

away from our home, and into the wider world.

Our ancestors did something which is actually remarkable.

From a beach not unlike this one,

possibly quite close by,

they ventured out into an open ocean,

with only an empty horizon in front of them.

And after many days and nights on the water,

they eventually came upon this new landmass that they would settle.

We call that landmass Australia.

It was a pivotal moment in the history of our species.

But in so many ways, it's not actually the destination

that's important.

It is everything it took -

all the challenges they had to overcome

to make it so far away from where they began, in Africa.

We were not the first humans to leave Africa.

Long before we evolved,

the ancestors of our cousins,

the Neanderthals, set out.

And Homo erectus, one of the most ancient humans,

had made it deep into Asia.

But none had ever made the voyage to Australia.

Every other species of human reached a point, and then they just stopped.

They faced a barrier that they either could not or would not pass.

But not us.

This is the story of how, time and again,

we took on perilous journeys -

how the last species of human to evolve

took on environments like no others had,

to become the only global species of human.

That title is ours and ours alone.

This story begins over 120,000 years ago.

As our species spreads beyond the borders of Africa...

..they're blocked by expanses of oceans on most sides.

One of the few places they can go is east -

to the vast landmass that today is made up of

Arabia and the Levant...

..at this time one of the few gateways out of Africa

to the rest of the world.

Of all the species of human that have ever existed,

I think we, Homo sapiens,

are the explorer species.

We can't help it - we have to wander.

It is in our wont to travel.

And this place was the landmass next door.

You could see it from Africa.

And look at it! It is absolutely breathtaking.

But it's not exactly welcoming.

Nothing about this place says home.

And so, the question is,

why did Homo sapiens come here?

We know they did,

thanks to finds from Israel and Saudi Arabia,

to the Gulf States.

And even beyond - to the fringes of Europe and Asia.

Which is hard to explain,

when today these lands look just as much of a barrier as any ocean.

I always say archaeology is a bit like a jigsaw puzzle,

and you're just constantly looking for pieces of that puzzle

to help you get the full picture.

And this is one of those pieces.

This particular piece is

a copy of a tooth.

Now, it's a single tooth, which gives you an idea

of how large this animal must have been,

because it's bigger than a brick. It's...

I mean, it's practically the size of my head.

It is the tooth of an extinct elephant,

and it was found in Jordan.

And we also have hippo fossils

from the Saudi desert.

Now, hippos and elephants

do not belong in this landscape.

Look around!

Where's the water?

Hippos actually need standing bodies of water,

and they need greenery.

And that's the thing about some fossils.

They tell us about what a landscape used to look like.

Because these do not belong here.

These finds point to a very different Arabia.

One that, if you know where to look,

you can see hints of to this day.

If you look over there, it almost looks like a mirage -

that white and silver on the landscape.

So that used to be a lake,

and the white and silver is actually salt and gypsum

that was left behind when the water evaporated.

And scientists are really interested in not just ageing them,

but also working out these ancient water systems -

these extinct water systems.

And so one of the ways they do this is by just getting on the ground

and walking these beautiful but incredibly intense landscapes,

looking at maps, looking at satellite images.

And this is the result of some of that work.

Now, if you look here,

this is a map of the region

just slightly north of here.

So this is Saudi, which is to our east,

and that there is the Sinai of Egypt.

You can see it's basically shades of beige and grey.

Now, look!

So this is about 125,000 years ago.

Water litters this landscape.

I mean, you can see the veins just running through.

There is no way that this land

would not have been green.

There are paleo lakes and paleo rivers absolutely everywhere.

And this is this region as we have never known it.

Now, remember, this was a world without borders,

and this was a land of plenty,

within easy reach.

And so why wouldn't Homo sapiens have come here?

But what they didn't know,

what they couldn't have known,

is that this region would be a trap.

The green days of Arabia were numbered.

The desert was on the march.

Subtle variations in the orbit of the Earth

caused the climate to change.

Within as little as a few hundred years, the rains vanished,

starving this entire region of water...

..leaving humans at the mercy of the desert.

If you set out to create an environment that was completely

and utterly hostile to our biology,

you'd come up with this.

The heat is such a presence

that I can feel it on my back.

The sun, even at this time of the morning,

feels like it's borderline torture.

And there is no water.

As far as the eye can see, there's nothing.

And back then, it would've been so much worse.

It wasn't arid.

It's what we call hyper arid.

It's thought that there was no rainfall for years on end.

And so we go from seeing multiple sites

where humans lived in this region, to nothing.

We seem to vanish for thousands of years.

And this could so easily have been the end of our journey...

..defeated by the harsh desert.

We think that some Homo sapiens

clung on in pockets that we call refugia.

Those are refuges where the climate is milder.

But from all we can tell,

they would've been few and far between,

and they effectively faded away.

And so, for all intents and purposes,

Homo sapiens outside of Africa had failed.

And what's interesting is

other species of human had cracked

the code of living outside of Africa, but not us.

And so how did this happen?

People like me, so many of you,

how did we become the only species of human

who exists across the globe?

These brutal conditions

persisted for years on end.

Until finally, there was another subtle change in climate...

..allowing conditions to become less extreme...

..and giving Homo sapiens another chance.

Occasional seasonal rains returned...

..just enough to bring precious water back to the desert.

Now, the conditions here did get better.

So, yes, you had desert and sand dunes...

..but you also had lakes and rivers.

And that resulted in us being able to exist in this place,

but not just exist here.

From an oasis here to a river and spring system there,

we were able to actually leave the Arabian Peninsula

and face the rest of the world.

As they did, these new waves likely absorbed any small pockets

of Homo sapiens that had held on.

And now scientists studying the genetic code

of people alive today believe this moment

was a pivotal point in our history.

Our DNA has the power to tell stories about us,

but some of them aren't just stories, they're sagas,

and they're extraordinary.

And one of them is that every single one of us

whose origins are from outside of Africa

comes from a tiny population of Homo sapiens.

We started in Africa, from multiple populations across the continent,

but then only a small group of us left -

perhaps as few as 10,000 individuals.

And so all of us from outside of Africa

come from this minuscule population,

who went on to populate

not one, not two continents, but five.

But our journey through the desert...

..was only one of a multitude of challenges

Homo sapiens would face

as we spread across the globe.

And because we were so few in number,

our very survival outside of Africa

was far from certain.

As this tiny population grew and spread...

..they would crash into another extreme environment.

One that had defeated all other species of human -

a vast green wall.

Once beyond the desert,

our species found themselves in the giant landmass of Europe and Asia.

To their north, lay high, cold mountains.

So many spread eastwards and south,

down through what is now the Indian subcontinent,

reaching modern-day Sri Lanka,

at that time joined to the mainland

by lower sea levels...

..and dominated by expansive dense rainforests.

And while this may look so much more welcoming than the desert,

nothing could be further from the truth.

These leeches are absolutely everywhere.

And when I say everywhere, I mean, one has just got me.

And there are creepy crawlies absolutely everywhere,

including in our trousers.

And they are actually quite irritating.

This place is also full of mosquitoes.

We saw a viper, and a cobra.

And that's the thing about this place.

It is difficult to exist in.

It's hot, it's humid, it's oppressive,

and you have to constantly have your wits about you.

This is one of the most extreme environments on the planet.

So much of what grows here is poisonous to eat...

..and there are few large animals to provide meat.

Conditions so difficult

that, as far as we can tell,

no other species of human

ever made it past the fringes of these rainforests.

Being here is a bit like stepping back in time,

because about 50,000 years ago,

this place would have basically looked the same.

This huge cave mouth would've been here.

Only back then, the rainforest would've been unbroken,

and it would've gone on for kilometres

in every single direction.

And yet, somehow, in this cave

and two other caves not far away,

we have found evidence of our ancestors living here,

all the way back then,

in the heart of what would've been a massive rainforest.

So how were Homo sapiens able to plunge into a place no others had?

How did they find food - particularly meat?

They did have the advantage of bow-and-arrow technology,

which had arisen thousands of years earlier.

But heavy, stone-tipped arrows

were less suited to firing into the high canopy of the rainforest.

Their solution was uncovered thanks to over 30 years of excavations

deep into the floor of this - and the two other two caves.

Digs that reach all the way back

to 48,000 years ago,

when the pioneers of our species

first attempted to overcome the challenges of this rainforest.

Starting with one of the most difficult -

how to find enough meat to sustain them.

Yeah. So, this here, that's where somebody is cutting?

- Yeah, yeah.

- Yeah.

Yeah. It's funny, because I think butchery marks,

often need to look at it through a magnifying glass, but not always.

And actually, this one is quite clear.

And this is not the kind of thing that you would see

if an animal killed it.

This is an indication that this is killed by a human.

And so the question is how they killed them.

Right.

So, that chip mark there...

..shows us that it was actually used. - Yes.

- I mean, it's amazing, because this is obviously...

I've got in my hands right now

something that was used 48,000 years ago.

- Of course, of course. - And it was absolutely revolutionary.

These bone points are only the tips of the full arrowheads.

Many are chipped from actually hitting prey...

..and each one would have been attached to the end of a long wooden arrow.

These hunters didn't invent a brand-new technology...

..they adapted an old one.

These are some of the earliest examples of bow

and arrows found outside of Africa...

..enabling Homo sapiens to hunt

with exceptional skill and efficiency within the forest.

But we know that the humans living here

were doing more than just surviving.

Oshan and the team also found beads fashioned from shells.

Perhaps brought in through trade from groups living on the coast.

A constant struggle to survive...

..doesn't leave much time for making works of art..

..suggesting a long-established and successful community existed here.

And for that, to turn this place into a true home

would take something fundamental to our species.

This is...

..a replica...

..of a tool that was found in the caves

in this area, dated from about 40,000 years ago.

It is a monkey tooth, specifically a canine, but that's been modified.

If you look here, it's been cut into,

to create a much sharper point.

And the reason for that...

..is that it's a tool used for puncturing.

Oh.

It's not easy.

All right, look, I've finally managed to make a hole.

And once you make a hole, you can then use plant fibre,

animal sinew, as a string, start stringing animal skins,

animal hide together, and create clothes.

But actually, in so many ways,

that's not the most interesting thing about this tool.

Because for me, the most interesting thing is what this tells us

about the minds of the people who have made it.

Because you have to be taught how to use it.

You have to be taught how to make it.

So it actually tells us something much deeper.

Throughout the years humans made this cave their home,

countless elder generations

would have taught children these techniques.

Something we still do to this day.

A communal passing on of knowledge that is key to our ability

to master so many different environments.

That engagement, constant engagement,

turns every generation of children

into a step in the evolution of knowledge.

And for us Homo sapiens, that's probably what adaptation is,

the evolution of knowledge,

because it's what turns a simple projectile like a bow and arrow

into a weapon fine-tuned, honed, and specialised for the rainforest.

And that constant innovation unlocks resources that were

completely out of reach to other species of human.

Resources like the rainforest.

And it's this ongoing evolution of tools

and techniques that has allowed our species, time and again,

to live and thrive even in extreme environments.

That is the strength of our species,

that we were opening up so many new environments,

places that previously other species saw as impenetrable,

as too difficult, we saw as having long-term potential,

and we were able to expand in number,

we were able to then adapt to it.

And as we grew, some people would decide to move on

to yet another environment.

We were becoming a species with truly global potential.

It was that ability to take on so many different, challenging

environments that carried us through so much of the world...

..by now, to the fringes of Europe...

..into the cold expanses of northern Asia...

..and, within only a few thousand years of leaving Africa,

deep into Southeast Asia.

Lower sea levels had created a single region known as Sunda...

..where today there are sweeping stretches of tropical waters.

Our wandering feet brought us to its outer edge.

Beyond lay an ocean, dotted with isolated islands.

There are these places that you turn up to and you think,

"I'm on the edge of the world."

They are incredibly remote and isolated,

and this is one of those places.

And it's been like this since the very beginning,

since its formation,

because it's been surrounded by this very deep sea,

which makes what was found here even more intriguing,

because a mind-boggling, completely unexpected human history

plays out here over hundreds of thousands of years.

Even all those years ago,

the ocean could not stop the spread of our species.

We reached these remote islands, thanks to a technology that,

as far as we can tell, we are the only humans to master.

This is a tuna fish bone.

This particular one happens to be quite fresh.

It's a few days old.

But we have actually found tuna fish bones on an archaeological site

on these islands that dates back to over 40,000 years.

But tuna swim in open waters, and that means that our ancestors,

over 40,000 years ago, they were fashioning some kind of vessel,

and going out into the open waters,

and coming back again, and again, and again.

We can't be sure what form these vessels took,

since no evidence survives,

but they were probably simple rafts made from available wood.

And they did more than just help us fish.

There is a very interesting archaeological site

on one of the neighbouring islands that has this one layer

that is just filled with artefacts belonging to Homo sapiens.

But the layer just before it,

immediately preceding it, is empty and barren of those same artefacts.

So it almost suggests that our ancestors just kind of turned up

overnight and spread rapidly through these islands in large numbers,

just because of the sheer volume of artefacts within that layer.

And none of that would really be possible

unless you were skilled enough to build robust craft,

you were skilled enough to navigate treacherous waters.

But in a truly surprising twist, we were not the first to reach Flores.

Somehow, someone made it here before us.

Sometimes in this job, you get to fulfil a lifelong dream,

and one of them is about to happen.

See, there's this cave in palaeoanthropology that isn't

just fascinating, it's basically explosive.

It started in 1950,

with this one priest called Father Theodor Verhoeven.

Now, back in the day, it was actually quite common

for priests and missionaries to also dabble in archaeology,

so he was out here on Flores looking for archaeological sites.

And in talking to locals,

he got told about this one cave that had potential.

He turned up, it was actually being used as an amateur school,

but just below the surface, he did actually find archaeology.

Actually, it was stone tools belonging to ancient humans.

Now, that in of itself is huge, it's really significant,

but it would take another half a century before we understood

just how important this cave was.

For over 20 years, a joint Indonesian and international

team of archaeologists has been excavating these caves.

They had been searching for evidence of the spread

of Homo sapiens through the islands.

Instead, they found something completely unexpected...

..a strange skeleton from at least 70,000 years ago.

So long before our species reached this far from Africa.

I think the first thing obviously that strikes you

when you see her is that she's very short.

Um, what are we talking, one metre?

Right, so about three and a half feet? - Yeah.

- It's got wisdom teeth. - Yes.

- Yeah. I mean, the molars are... The adult molars are there.

Yeah, yeah, yeah.

As soon as you look closely, this is 100% an adult.

- Yeah. Yeah.

- An adult, but the size of a child.

And that was only the first surprise.

The legs, they're quite short. - Yeah.

- Whereas, with us...

Our legs are really long...

..compared to arms.

Yeah.

Yup.

Which is huge... - Is huge, yes.

- ..because on me that would be about that length.

I mean, this is one of those moments in the history of the field

where I just wish I had been there.

I know she's a replica, but she's a replica of the real thing,

and, yeah, it's...

It's giving me goose bumps.

This new species of human was a revelation.

Named Homo floresiensis, after the island,

they quickly became known to many as "the hobbits," after the

heroes from the Lord of the Rings, who were also small as adults.

It's likely they arrived entirely by chance. Perhaps a few

individuals swept here on driftwood from the islands to the north...

..more than 700,000 years ago.

Eventually becoming a unique species,

seemingly with a mix of modern and more ancient characteristics.

Now, we can see obviously the brain is small,

but how small are we talking?

That... - That's right. - How incredible.

Such a small brain, and yet they had stone tools.

Before this, scientists assumed that a human with such a small brain

could never have developed such tools.

One theory is that they were initially a much larger

species, before the long isolation on Flores caused them

to shrink, a process known as island dwarfism,

where large animals get smaller due to fewer resources.

At the same time, some small animals actually get bigger,

due to a lack of predators.

So Stegodons generally are not the size of water buffaloes.

- Exactly, yeah. - But on this island...

- It's big one. - ..they're the size of a water buffalo. - Yeah.

- And then on this island, you've got humans that are a metre tall.

- Yeah, that small.

- What you're describing there is a species that has been

shaped by this island, has been

shaped by the environment on this island, and the result is this.

Long isolation allowed evolution to tailor the hobbit

to this environment.

Their long arms, compared to short legs,

a response to perhaps the steep terrain,

or the lack of predators on the island to run away from.

Physical adaptations that, along with those simple stone tools,

helped them survive here for hundreds of thousands of years.

You can see, it's like layers of cake. - Yes.

- So every period has left a layer.

So this is like a snapshot in time, telling us

a lot about different periods.

That's basically flow from volcanic eruption?

- Yeah.

- Mm-hm.

Right.

Right.

So Homo sapiens.

That's really significant.

So the pyroclastic flow is when you have the gas

and material that comes from a volcanic eruption,

and really, I mean, that would just be quite destructive.

- Yeah.

- We don't think that that final eruption alone caused

the extinction of the hobbits.

It would have been a catastrophic event here at the cave,

but we don't know how it affected the rest of the island.

What we do know is that this shows the time of the hobbits here

was coming to an end.

So you're looking at actually quite a different world down there,

to up there. Yeah. - Exactly, yes, exactly.

- This tiny island has been home to two species of human.

One remains to this day.

One vanished long ago.

It is wonderful to imagine what this place was like before all of this.

Thousands of years before our ancestors, you had these

miniature elephant-like creatures who wandered open grasslands.

You had actual dragons, the Komodo dragons, who still exist.

And then giant marabou storks - storks that were carnivorous,

that were my height or taller, and could fly.

It was like a fantasy island.

And amongst all of it,

there were these humans who were tiny, who came up to about my hip.

And those hobbits lived here on this island for a staggering

length of time, potentially for more than 700,000 years,

longer than we've existed as a species.

And yet, there is this twist, because so far,

we have found no evidence of them past these shores.

Their whole story plays out only on this island of Flores.

Our own species, in just a fraction of that time,

was able to spread across a huge portion of the globe.

Around 50,000 years ago, the climate here became warmer and drier,

changing the environment.

At the same time, those violent volcanic eruptions also struck.

Whatever the reason, it meant that Homo floresiensis faced not

just change, but rapid change.

That meant that their physiology, their physical adaptations,

that for so long had been a benefit, were now a trap.

They were being left behind, because it's actually incredibly

difficult to rapidly evolve your way out of a sudden crisis.

And they couldn't behaviourally adapt to this change either.

Nor could they, say, escape and move to another island.

And so these wonderful, fantastic relatives of ours vanished forever.

And in their place, Homo sapiens appeared, making this island,

like so many places, their home.

So far, we've found no evidence that our two species overlapped.

But for many, the final factor in the hobbit's extinction

is likely our sudden arrival.

The hobbit simply couldn't compete

with this highly adaptable newcomer...

..a species able to change its behaviour

to suit almost any environment and condition.

The very characteristics driving our continuing spread across the globe.

As we spread further and further away from Africa,

entering into brand-new environments

that we had never experienced before,

we're not just surviving in these places,

we're actually setting down roots.

And roots that would last us till this very day.

There was one last part of this journey to go.

We set out on a path no other human species had travelled...

..perhaps following tantalising hints

that there was more land to explore.

Clouds on the horizon, returning flights of birds...

..or maybe something much more instinctive that inspired,

we think, dozens of families to strike out on a voyage that

would carry them to a new continent...

..Australia.

Now, these were people who were comfortable on the water,

they were going from island to island,

but Australia was something different.

We're talking about a journey that was up to 100km,

60 miles.

That's days and nights on the open ocean,

probably in something as basic as a raft that was perhaps being

propelled and steered with just paddles.

Launching out into that hostile and expansive ocean,

that would be an expedition today, let alone back then.

When I think about the risk involved,

when I think about the emptiness, it is just absolutely astonishing.

The islands of Indonesia were another waypoint

in our ongoing journey.

Our unique adaptability that helped us cross the harsh deserts...

..and break through the barrier of the rainforest...

..now carried us practically to the ends of the Earth.

To Australia, around 9,000 miles from where we began.

Which does beg the question, what kept driving us on...

..ultimately inspiring us to take on the dangers of the open ocean?

It's true that there will often have been a push.

The simple need to find new resources

for our expanding population.

But I would argue that that is not the full explanation,

that this is the most intangible part of the story.

See, these people, in my opinion, were just like us,

so they had the same fears and hopes for their families.

We are clearly the explorer species.

I think that is beyond a doubt.

And, as a result,

we have been able to take on things that seem absolutely impossible.

In that desire to understand what was out there,

in the thrill and excitement of understanding the unknown,

and the willingness to take risk to know it.

See, wanderlust, creativity

and the imagination required to put yourself in a different place,

into a different future and world, I think that is fundamentally us.

We chart the spread of Homo sapiens into the expanses of Europe

as our species struggles to survive in the grip of a cruel Ice Age

and comes face-to-face with another sophisticated species of human...

..the Neanderthals, who had long mastered life in these cold lands.

In this episode, we filmed at a place I've long dreamt of visiting,

one of the most important human archaeological sites of all,

Liang Bua cave...

..where scientists are still trying to solve the many mysteries

surrounding the hobbits, the ancient humans that lived here.

In 2004, their discovery sent shock waves through

the scientific community.

- So, the moment the paper's dropped, it was massive.

It was all over the news.

It was all over the internet.

Everyone was talking about this tiny,

unexpected hobbit from Indonesia.

- Paige has known Thomas and the team since 2017,

documenting their research.

Like many scientific breakthroughs,

the initial discovery created intense controversy.

- The conferences got extremely heated.

Sometimes there would be hobbit sessions where within the same

session, you would have a few talks would be sort of pro hobbit -

so, "This is a new species, this is really exciting,

this is changing a lot of what we thought we knew

about human evolution" -

and then in the same session,

you would have people that are saying,

"This is the biggest mistake

"that human evolution scientists have ever made."

- Many argued that this was not a new species,

but a Homo sapiens suffering from an illness that caused its small

physical features and brain size.

Eventually that was discounted, and Homo floresiensis was recognised

as a new species of human - raising, if anything, even more questions.

- We still don't know, for example,

where they came from or who they're closely related to.

So that question of the origins of Homo floresiensis is still,

I would say, almost completely an open one.

- It's possible they evolved from another ancient

species of human, such as Homo erectus,

which we know was in the area just over a million years ago.

Perhaps carried to the island by chance,

and then shrunk down over many years of isolation.

But there is an even more controversial idea.

- If you look really hard at a lot of the characteristics,

particularly below the cranium...

..you see that this is a creature

that looks a lot more like some of our really ancient ancestors,

more than two million years old, in Africa.

And so maybe there was an exodus out of Africa a million years

before we thought there was.

- This current dig might reveal the answer.

With help from the Max Planck Institute in Germany,

researchers are trying to collect fragments of hobbit DNA.

- Ancient DNA is really helpful at really laying out

relationships for us between different species across time.

And so, because of the way that mutations accumulate over time,

it allows us to kind of work backwards

and trace back when some of those lineages would have split.

Homo floresiensis, and whoever their closest ancestor is,

which is not a question we can answer until we kind of

have some of that information.

- The problem is successfully finding hobbit DNA will not be easy.

- Normally it would be impossible to recover DNA from a situation

where it's this hot.

It's just too difficult.

DNA degrades really rapidly, and other things move in

and muddy up the signal, like bacteria and other things.

But in this cave in particular,

it is at a slightly higher altitude than a lot of Indonesia is,

it's right up in the mountains,

and so it is a little bit cooler than most equatorial areas.

And so there is a little bit of hope that we might be able to

get a little bit of a signal from the species.

- If successful, we might finally solve the mystery of the hobbit.

Whatever happens, Homo floresiensis will remain one of the most

important and unexpected discoveries of recent history.

LABOURED BREATHING

CRY OF PAIN

GRUNTING

GROANING

BABY CRIES

Around 30,000 years ago, a child was born into a new and lonely world.

They were the first child to be born onto a planet

in which we were quite alone.

This was the first time in history that only one species of human

walked this Earth.

All the others were now gone.

And in a tale written by the sole survivors,

it's actually quite easy to forget

that we weren't destined to be the only ones.

And yet here we are.

How this happened is one of the most poignant chapters

in the human story.

And it's one that's etched into the DNA

of every single one of us alive today.

For hundreds of thousands of years,

Homo sapiens evolved in Africa.

60,000 years ago, one group dispersed into the Middle East...

..and continued onwards as far as Australia.

But our ancestors didn't stop there.

Another group began to make their way north into Europe...

..where their story continues.

For thousands of years, Europe had been out of reach to Homo sapiens...

..repelled by its icy climate.

But now a shift in conditions opened up a route

into this new realm.

And some of our ancestors left the familiar behind...

..and stepped into the unknown.

We don't really know why they came.

Was it a romantic notion, like pure curiosity?

Or was it something much more practical? Say, the need for food.

Or perhaps it was the same forces that drive migrants today -

that need for shelter and safety.

We don't know the exact routes they took,

but by following rivers, coasts, or wandering across mountain ranges

like these, they found their way into this new world.

But not long after these migrants reached Europe...

..they would have encountered something unexpected.

When they got here,

they would have discovered that another species had beat them to it.

Two other human species were widespread at the time.

To the east, from Siberia to Southeast Asia,

lived the mysterious Denisovans,

known only to us from DNA

preserved in a few fossil fragments.

Across lands to the west, all the way from Russia

to the Atlantic coast of Europe, were the Neanderthals.

Homo sapiens were latecomers to Europe.

It had been home to the Neanderthals for almost 400,000 years

before we showed up.

Now these Homo sapiens venturing into Europe would have met

another sort of human.

People who looked a lot like us, but with obvious differences.

We can only imagine what our ancestors would have made of them...

..when our two cultures - perhaps just two families...

..encountered each other for the first time.

Neanderthals were close relatives of Homo sapiens,

but we had evolved along separate branches of the human family tree.

There's often this belief that we evolved from Neanderthals,

so we came from Neanderthals.

Actually, that's incorrect.

We shared a common ancestor with them.

And then, due to chance and the environment,

we went on these two really different evolutionary journeys.

So, we evolved - Homo sapiens - for Africa.

We ended up taller and leaner.

Now, the Neanderthals evolved for much cooler,

more wooded environments.

So they were shorter -

on average, they were about 5'5" -

they had bigger torsos, but shorter limbs.

They used a lot of brute force...

..because they were close-range hunters.

The Neanderthals were masters of their environment -

they had evolved here for hundreds of thousands of years -

whereas we turn up and we're immigrants,

we are ill-equipped and unprepared.

If you were going to place a bet on who would be left standing,

you'd probably bet on the obvious choice - and it wouldn't be us.

The Neanderthals had found a way to thrive here for millennia.

Yet in the 19th century,

when the first Neanderthal fossils were unearthed...

..we quickly made assumptions...

..that have persisted ever since.

As a result, Neanderthals haven't had the best PR.

If somebody calls you a Neanderthal, it's probably not a compliment.

And that stereotype of Neanderthals has been with us

since the very beginning.

And it kind of suited us to see ourselves as the pinnacle

of evolution, and them as these knuckle-dragging ape men.

But partly, that stereotype is actually just a mistake of science.

Palaeoanthropology at the time was quite a new science,

and when they came to reconstruct this one Neanderthal called

La Chapelle-aux-Saints, they portrayed it as kind of really

hunched over and knuckle-dragging, which was just wrong.

This kind of brutish, hairy Neanderthal,

looking like it's about to attack, it's incredibly aggressive.

And then Hollywood pick up this stereotype.

Some of these images are so ridiculous.

Very monkey-like Neanderthals.

That impression of Neanderthals just solidifies.

I personally love Neanderthals,

and the more we learn about them, the more we study them,

the more we discover about them,

the more we realise that this is actually incredibly incorrect.

This now outdated image of the simple brutish caveman is

finally being replaced...

..with a picture of a once vibrant, thriving culture.

There may be no Neanderthals left to tell their story...

..but thanks to the traces they left behind,

we can begin to imagine people who aren't so different from us.

We keep finding things at Neanderthal sites

that really challenge us.

Things like beaded shells with pigmentation on them,

almost like they're being used as necklaces.

Eagle talons that have been polished down.

And then there's my actual favourite, which is

evidence of feathers.

But not just any feathers.

No, the Neanderthals seem to be really

interested in iridescent feathers from things like red kites.

And you've got to wonder,

why were they so interested in those particular colours?

And it's presumably because they're high value.

They're beautiful.

You kind of have an impression of them as having these incredible

headdresses or maybe cloaks made of these brilliant, bright feathers.

When you put this all together,

you paint a picture of a Neanderthal, not as this

aggressive creature standing behind a rock with a massive club,

but actually as these beings very interested in adorning themselves.

Interested in looking beautiful with necklaces

and gorgeous coloured headdresses.

Suddenly you're looking at beings who aren't just

interested in food and shelter -

they're interested in the way they are seen by the world.

This - all this - makes them tangibly human.

For generations, Homo sapiens and Neanderthals lived

near one another.

But how close were we?

For decades, most assumed interbreeding

between our two species didn't happen.

But in the early 2000s, this was called into question...

..with the chance discovery of fossil fragments...

..which revealed humans with a mysterious mix of features.

It even smells like a fossil.

This, I assume, is Oase 1.

- This one is Oase 1.

- And that's Oase 2. - Skull. That's Oase 2.

- This is quite special because I've read about them.

I've studied them.

They're hugely significant fossils,

but I've never seen the originals.

I've never been this close to them. It's...

- We excavated for two years.

We unearthed, like, more than 10,000 fossil remains,

mostly cave bear, but also Oase 2.

And it looks and it is modern Homo sapiens. - Yeah.

- But it has some features which are more like Neanderthal.

- Yeah. - Like this one. It's quite clear.

It's a mandible of a modern human with this chin.

- Cos there's a chin. - Yeah, a chin.

Yeah. - And Neanderthals don't have a chin.

Neanderthals' chin kind of recedes.

- But then you see the size of the molars... - Yeah.

- ..which are really huge. - More a Neanderthal feature.

- Modern sapiens, but with Neanderthal teeth.

Yeah, Oase 2 has the same hybrid features. - Mm-mm.

- Like if you look at the face.

- You look at that and you do think that's Homo sapiens.

And then it has these features on it, which are more Neanderthal.

Like this occipital bun here at the back,

that bulge at the back of the skull here.

- Yeah, that's kind of strange.

It's not a Neanderthal, but it has Neanderthal features,

which prompt us to think about some sort of interbreeding.

Neanderthal, Homo sapiens interbreeding.

It was pretty controversial.

- People thought it either didn't happen,

because we were too genetically distinct.

- People were just not ready to accept that.

Interbreeding is not something uncommon in biology.

It happens with other species.

At that time, it was somehow taboo.

- Around a decade later came a revolutionary breakthrough.

Advances in genetic analysis allowed scientists to extract

DNA from ancient fossils...

..proving these two species could - and did - produce offspring.

How did it feel to be proven right, to be vindicated,

especially over something so controversial?

- We felt relieved. - Yeah.

- Like, "OK.

"Now you know."

Yeah, we were happy to be right.

- Yeah.

How many generations ago was the Neanderthal ancestor?

- We now know that this individual had

a Neanderthal ancestor somewhere back four to six generations.

- One of the great-great-grandparents, potentially, was a Neanderthal.

- Something like that.

- You know, people spend their whole lives - their WHOLE lives -

trying to find a fossil as significant as this, and...

Wow, it's just amazing.

Since the discovery of Oase 1, evidence has continued to grow,

proving hybrids like this were not just possible,

but may have been relatively common.

We'll never know the full story of Oase 1 and the other hybrids,

and to be honest, we'll never know the full circumstances

under which they were conceived.

For all we know, it could have been nonconsensual, or it could have

been the result of a romantic notion like love,

or it might have been the result of a practical decision

like as part of a trade agreement.

But whatever it was,

what must it have been like to have been a hybrid child,

to have had a parent or grandparent or great-great-grandparent,

not just from a different race, but a completely different species?

Did these children feel like they belonged,

or were they teased and ostracised?

We'll never know, but what we do know,

because I held Oase 1 in my hands, is that they existed.

And so somebody loved them,

and somebody was raising them to adulthood.

And so we tangibly know that the Neanderthals

and the Homo sapiens, they didn't just meet - they joined.

We now know that, for a time at least, Homo sapiens

and Neanderthals managed to live alongside one another.

But a global change would push both species to the limits of survival.

It's likely Homo sapiens arrived here during a brief thaw.

And by doing so, they had walked into a trap.

Europe was plunged into winter.

Unrecognisable to us today, it became a barren and hostile world.

Rainfall in some areas fell to half its modern level.

And much of the continent became tundra.

A vast, inhospitable plain.

All of a sudden, Homo sapiens were confronted by

a completely different world.

Frozen, relentless,

and utterly unexpected.

There's no way for them to have known it,

but before the first Homo sapiens arrived,

most of Europe would have been in the depths of winter.

Ice sheets like this one would have spread from here

all the way down to Britain.

Homo sapiens evolved in Africa,

so these conditions would have been completely shocking to them.

It's currently minus eight degrees.

I am wearing so many layers, it's actually ridiculous.

And yet, I am still completely miserable.

It is so cold, I can't feel parts of my face.

These families, they were here

and they were trying to keep young children alive.

These conditions would have been life-threatening.

But while Homo sapiens weren't adapted for the cold...

..Neanderthals had evolved to survive brutal

winters for almost 400,000 years.

They knew where to shelter and hunt for scarce food.

But survival was also in their biology.

It's thought they evolved to store more brown fat than Homo sapiens.

This burns more calories and generates heat,

conserving energy in the cold.

And larger nasal passages acted like natural radiators...

..warming and moistening the icy air before it reached their lungs.

When the going got tough, Neanderthals were built to endure.

Without the Neanderthals' adaptations or knowledge,

these early European Homo sapiens would have been doing

everything they could just to cling on.

And yet the bitter cold was just the beginning.

This glacier is the remnant of an ice sheet that's incrementally

grown and shrunk for millennia.

Deep within are clues about the world our ancestors

would have found themselves in.

- We're working in mountain glaciers like Folgefonna

because we can use the evidence of how the glaciers have changed

in the past to understand how they behaved

in response to climate change.

Many of the places we live in now, where I live in Bergen,

would have been underneath a kilometre of ice. - Yeah.

I mean, there were times when Britain was part of that.

- The ice sheet came as far south as about Birmingham.

- Birmingham, my own hometown. There we go!

- So, this is where we're drilling the ice core. - Yeah.

So, it's manual drilling? - Yes, exactly.

And there's blades at the bottom that are cutting through the ice.

- How tough is that? - It can be quite hard work. Yeah.

And then we lift it out, and we bring it over here.

We can see... - Look at that.

- If we hold it up to the light, we can see the air bubbles.

- So basically, this is effectively a time capsule. - Yes.

And this is young ice from Folgefonna glacier.

But if this was from Greenland and it was deep, old ice core,

those air bubbles would tell us about what the atmosphere

was like in the past.

We can look at what we see from the ice cores in Greenland.

And this shows us how the climate

changed through that period in the North Atlantic region. - Yeah.

- There was a relatively cold

but stable climate from 70,000 to 60,000 years ago.

And then between 60,000 and 30,000 years ago,

the climate in this region jumped by eight to ten degrees warmer over

maybe one or two decades. - That's quite a lot.

- It's huge. It's huge.

And that cycle is repeated all through that period.

And then it cooled again and then jumped.

And this carried on.

And we see then a cold, but slightly more stable,

climate before we then warm into the present day.

- I mean, how do you exist

if the climate changes like that in such an extreme fashion?

- Well, it's very challenging.

It's maybe not even possible because everything you know

about how to live, how to raise children,

becomes in 10-20 years... - Yeah. Obsolete. - ..totally changes.

- Yeah, yeah, yeah. - Totally changes.

- Entire ecosystems collapsed.

Forests became barren plains.

Lakes dried up.

And rivers froze over.

The real enemy wasn't cold.

It was chaos.

As landscapes shifted, herds of animals disappeared.

And sources of food grew scarce.

People were driven into unfamiliar territories

and forced to compete for what little remained.

It was a brutal time to be alive.

Imagine what it would be like for our ancestors to live in this

world where the land of their grandparents was not

the land of their grandchildren.

And when that happens, intergenerational knowledge -

knowledge that's passed on from one generation to the next,

that's so important for survival in these environments -

suddenly that knowledge isn't actually very useful

because the plants, the animals, the landscape, it's all different.

To survive, each generation had to discover the world anew...

..roaming further in search of dwindling resources

that might not be there.

Homo sapiens and Neanderthals would have been forced to find

shelter wherever they were able to...

..seeking refuge in the few habitable places they could find.

55,000 years ago,

the south of France was still in the thick of the Ice Age.

Yet, compared to the deep freeze of the north, it was

one of the more bearable places in an otherwise hostile landscape.

And here at Grotte Mandrin...

..archaeologists have spent over three decades

unearthing its secrets...

..layer by layer...

..revealing a place that was home to Neanderthals for more

than 80,000 years.

Shoes off. - Yes. - There we go.

Yeah.

Uh-huh.

So, what you're seeing here is phases of occupation

over 80,000 years. - Yeah.

- And because you've got incredible resolution, you can

really hone in on that.

Each layer has preserved a moment in time.

And from the treasures buried within,

it's possible to piece together different chapters of history.

For millennia, this cave was home to Neanderthals.

But one layer stood out, containing finely crafted tools.

Small and precise.

Techniques that suggested they were made not by Neanderthals,

but by Homo sapiens.

A suspicion confirmed when the Earth revealed another treasure.

That then is conclusive evidence that that layer with those

strange, unusual stone tools is definitely a Homo sapien layer?

- Yes.

- These discoveries tell us a story of one group of Homo sapiens.

Among the first to come to Europe...

..they had ventured into Neanderthal territory...

..seeking refuge in this cave in the depths of the Ice Age.

When we imagine the past, we often don't imagine children.

We imagine, well, a man, a caveman, right? - Yeah.

- But, actually, these were cave children. - Yeah.

- And you imagine what they were doing, were they playing?

- They were playing.

- But imagine to have been born, the first of your people

to turn up there - and we don't know,

they might have been born somewhere else - but... - Yeah.

- ..it's fascinating.

Wow.

Using advanced dating techniques, a team were able to uncover

even more precise details about the people who lived here.

So people were building fires... - Yeah.

- ..the fire created soot that would end up on the roof. - Exactly.

- And then bits of the roof would collapse

and end up in your archaeological layers? - Yes.

- It's literally telling you when they're using this place. - Exactly.

- By counting the microscopic layers of soot

deposited on the cave ceiling,

the team could tell how often these people came here.

But what happened to them?

This exceptional site tells the story of a group of Homo sapiens

pioneers who lived here in between tens of thousands

of years of Neanderthal occupation.

But then all traces of them vanished.

It's one small but very important chapter in our bigger story.

We don't know what happened to that particular group of Homo sapiens

from Grotte Mandrin, but it's likely that their story

reflects what was unfolding across the continent.

This wave of Homo sapiens was lured into Europe during a warmer spell.

They were pioneers for sure, but they were trying to

survive in a brand-new environment as best as they could,

as best as they knew how, really, finding temporary places to shelter

before in the blink of an eye moving on -

or worse, dying out completely.

Because that band of Homo sapiens from Grotte Mandrin

would be the last of our species found on this continent

for thousands of years.

Perhaps unprepared for the harsh environment they faced,

this early wave of Homo sapiens in Europe did not survive.

Once again, and for the next 9,000 years,

it became exclusively Neanderthal territory.

Neanderthals had survived while Homo sapiens died out in Europe.

Yet today, we're the only ones left.

How did our stories end so differently?

Part of the answer can be found deep

within the forests of northern Spain...

..where evidence hints that the grip of the Ice Age was

taking its toll on the Neanderthals.

A struggle uncovered in a cave known as the Tunnel of Bones.

Oh, wow.

So this is the famous El Sidron Cave. - It is, yes.

- It's got more character than I was expecting, actually. - Yes.

- And how did you find them?

Wow.

Such a diverse group in terms of individuals...

..all found in one spot.

And, you know, when you say that one of those people had red hair,

it suddenly brings what are just fossils, really, to life.

It's a cave that's filled with ghosts.

This was not a natural death.

Cracked skulls and precise cuts on the bones...

..suggest that this was a brutal massacre.

13 people killed by another Neanderthal group.

But closer analysis of their remains...

..revealed an even darker truth.

So what do the bones actually tell us?

They were really eating these 13 individuals? - Yeah, yeah, yeah.

- So how do we know that this was cannibalism as opposed to

just straight up murder - or, for that matter, an animal coming?

So you're looking for something sharp?

And now, you have a... - Yeah, that's it, let's see.

- Yeah. Yeah, yeah, yeah, yeah, yeah, yeah.

Yeah. So, they're focusing on the areas where there's muscle,

where there's meat, effectively. - That's it.

- Yeah. Oh!

Yeah, if you're getting bone marrow... - That's it, yes.

- ..that is an indication of cannibalism, for sure.

- Yes, it is, sure. - Yeah.

This murder/cannibalism of 13 members of a family group

isn't the only dark thing that's happening here.

That's unusual, that's a congenital anomaly.

So, basically, you've got an inbred population.

It's painting a picture, isn't it?

Of those...those final thousands... - Yes.

- ..thousands of years before they eventually became extinct.

Yeah, it's a silent killer. You're right.

The El Sidron bones hint at more than the suffering of one family.

Because this pattern of starvation, cannibalism

and violence was happening across Europe...

..this was a species in free fall.

This is a haunting place.

It's not exactly Neanderthals in their heyday, is it?

If anything, it's kind of like the end of days for them.

They've been driven into this evolutionary cul-de-sac,

reduced to eating each other

and having children with their relatives.

And that inbreeding would have made them more susceptible to disease.

If, on the evolutionary timescale,

12:00 midnight represents extinction for the Neanderthals,

this site is past 11:30.

This once resilient species...

..was now reduced to just a few isolated groups...

..turning on one another.

But any chance Neanderthals may have had of weathering this storm...

..was shattered by the return of another species.

Homo sapiens.

9,000 years after Homo sapiens had disappeared from Europe,

waves of settlers returned.

A new generation...

..who, even though the climate was as volatile as ever...

..were undeterred.

These were survivors, and they were here to stay.

Some archaeological finds,

their significance is immediately obvious, but others you don't

necessarily know what you're looking at until you suddenly do.

And this is a really good example of this.

This might not seem like a lot,

but actually it represents a massive step forward.

So what you're looking at here is

the imprint, in clay, of weaving.

Now we don't know if it was intentional -

it might have just been that there was some material on the floor

and somebody just happened to throw down some clay,

but they actually think that this may have been made with nettle.

And you're probably thinking, "Well, nettle, really?"

Well, that is probably a by-product of the modern world

and all the fabrics that we use, but actually this here is made of

nettle, and this is the woven fabric that they were able to make from it.

If you can make this, you can suddenly make better clothing...

..and you're able to protect yourself so much more from the cold.

Maybe those young children in a cold spell might have survived

a bit better if their clothing fitted better.

But you can't just think about weaving as being about clothing,

because if you can weave, suddenly your nets, your traps, are better.

You're able to get more food.

You're potentially able to make better shelter.

Whenever we talk about Palaeolithic technology,

you're probably thinking about spears or stone tools.

It's always weaponry, right?

Well, actually, this stuff might have really given them

the edge, as well.

It's likely the ability to make better clothing increased

infant survival, even in the harshest months.

Each advance, however small, added up...

..giving Homo sapiens the one thing Neanderthals lacked...

..strength in numbers.

The Neanderthals had existed for over 400,000 years...

..developing a rich culture...

..and withstanding brutal conditions for millennia.

But the relentless climate, dwindling resources...

..and another species growing in strength pushed them to the brink.

But what delivered the final blow?

How does an entire human species disappear

from the face of the Earth?

Part of the answer may lie in the smallest of things...

..the genes we exchanged in the form of our hybrid children.

I'm going to try and do a demo to explain genetics.

So let's see how this goes.

Let's say that these are the Neanderthals,

and these are the Homo sapiens,

and they interbreed.

We don't know where the hybrid children ended up.

Did they end up with the Neanderthals,

or did they end up with the Homo sapiens? So, let's just say,

they went back 50-50.

And we see a little Homo sapiens DNA in the Neanderthal group...

..and a little Neanderthal DNA in the Homo sapiens group.

The Neanderthals lived in small, isolated populations,

but the Homo sapiens were probably a little bit better

at keeping their kids alive.

And also, importantly, they were constantly replenishing

from source populations in the Middle East, Africa, and elsewhere.

Numbers made all the difference.

As more Homo sapiens migrated into Europe,

Neanderthals were already declining.

So, when the two interbred,

the impact on Neanderthals was far greater.

If you're a huge population, that interbreeding doesn't have

the same impact as it does on the much smaller Neanderthal population.

It's already a little bit interbred.

Perhaps they were simply absorbed into the larger Homo sapiens

population that just kept on replenishing.

Over time, Neanderthal DNA became increasingly

diluted by the much larger Homo sapiens population.

So, it doesn't actually need to be this big act of aggression.

It might just be the fact that we were there, that we

were interbreeding with them,

and that we had large population sizes.

Perhaps that was enough to push the Neanderthals to extinction.

It was a perfect storm for Neanderthals.

By around 40,000 years ago, their gene pool was diminishing...

..until only a handful of distinct Neanderthal populations remained...

..hanging on in just a few isolated enclaves.

We don't know where the last Neanderthal outpost was.

It was likely a very remote part of Europe or Asia.

But around 40,000 years ago, that place probably

acted as a refuge to the very, very last of their kind.

Archaeologists have pieced together what may be among the final

moments of Neanderthal extinction.

Uncovering remains of what could be

the last surviving Neanderthal groups.

Some of that evidence has been discovered

in coastal caves in southern Spain.

We don't know what truly happened in those final moments,

or who was left at the end.

But there was an ending.

Because after that, our sister species,

who had existed for around

400,000 years...

..vanishes from the archaeological record completely.

It feels like a moment of loss.

We lost something.

But also...

..it's part of the human story.

It's our story.

These were our ancestors.

On the one hand, it's hard not to be impressed with Homo sapiens.

And if we hadn't have been so successful, if we hadn't have had

this hunger to innovate, to explore, would you and I even be here?

And yet, those same things that make us so remarkable

seem to be damning to those around us.

This is where this chain of events ends.

A slow, unwitting war of attrition against our sister species...

..until they simply faded away.

But this wasn't the only ending.

After the last Neanderthals, the Denisovans -

the species who once spanned much of Asia -

may have survived for another 10,000 years...

..until they, too, were overwhelmed by Homo sapiens.

This story starts with three species, but it ends with one.

And it's part of a wider pattern that always goes the same way -

the survival of our species leading to the demise of everyone else.

Today, these events have faded from memory.

But it's not quite the end of the story.

Because we carry a piece of this history within us.

One of the most striking revelations over the last few years

is that everybody from outside of Sub-Saharan Africa

has about 2% Neanderthal DNA.

And that DNA is associated with negative things

like Crohn's disease,

but it's also associated with all kinds of positives,

like being better adapted to the cold.

And now we know that Denisovan DNA

has been found in Homo sapiens populations.

It's as high as 6% in the Philippines.

And it's associated with things like

being able to survive better at high altitude.

And if you think about it, it actually makes perfect sense.

Because when we were leaving Africa, the Neanderthals

and the Denisovans had already spent hundreds of thousands of years

adapting and evolving to their local environments and pathogens.

And so what we were doing by interbreeding with them

was effectively a quick fix.

We were adopting adaptations that would ultimately aid our survival.

Depending on where you're from, you'll probably find

traces of Neanderthal or Denisovan DNA within you...

..a genetic echo of the human story connecting us

to this long line of distant ghosts.

2% might not sound like a lot, but my 2% is different from your 2%.

And collectively, all of that Neanderthal DNA

that exists within humans living today

would make up about two-thirds of the Neanderthal genome.

And so in a very real sense, Neanderthals

and Denisovans have been assimilated into our bodies.

And it's just the loveliest thought, isn't it?

That they live on and exist within us.

Our planet was once home to many human species.

Bit by bit, they've all disappeared, leaving only one...

..the inheritors of their DNA.

..as the Ice Age reaches greater extremes,

we step into an unexplored continent...

..where new dangers lie in wait...

..starvation threatens...

..and humans have to fight to survive.

For 270,000 years, our species, Homo sapiens,

lived in a world inhabited by other types of human.

We hunted and foraged for food,

alongside many of our human relatives.

But one by one, we out-survived them...

..and spread across the planet as small bands of nomads...

..until we'd reached almost every corner of the globe.

But a great landmass still evaded us.

The Americas.

As we entered this new world, we would face ferocious predators...

..and towering giants.

MAMMOTHS BELLOW

But how we took on these challenges...

..and the ways we began to tame nature

in our journey through the Americas...

..would set us on a path to how we live today.

It's a chapter of our story

that begins in one of the coldest and most dangerous times

humans have ever known.

At the height of the last Ice Age,

a time when sea levels were lower than today,

people were spreading from East Asia

into a place that no longer exists.

A vast land bridge called Beringia.

WIND HOWLS

And in this frozen north,

small groups of travellers dispersed ever eastward...

..and found themselves stepping into a new land.

If you were asked to conjure up in your mind

a world that was magical, that was pristine, that was primal,

you'd imagine something like this.

The northwest coast of America absolutely takes your breath away.

We don't exactly know when humans first arrived in North America...

..but many archaeologists believe

it was sometime around 20,000 years ago.

A time when this would have been a challenging place to live.

They were here at one of the coldest moments Homo sapiens had ever known.

And the landscape would have looked so different.

There would have been very few trees.

And, as far as the eye could see,

there would have been barren, icy rock.

They knew how to survive

in the barren lands of Beringia that they'd come from.

But their new environment was different in a few crucial ways.

The northern half of this continent

was covered in a vast, towering ice sheet.

From here in the northwest,

this wall of ice blocked routes into the deep interior...

..largely confining people to the ice-free land nearer the coast.

WAVES CRASH

All that's left from their time here

are footprints, stone tools, and animal bones.

Now, we know that they sometimes would have hunted seal,

they would have eaten fish,

they would have eaten seabirds if they could catch them.

GULLS CRY

Only tiny fragments of evidence remain...

SLIDE PROJECTOR CLICKS

..that hint at how they survived.

And whilst this northwest coast

offered them steady but limited sustenance,

the strip of land between the shore and the ice sheets

promised new opportunities to find food...

..but also hid unexpected new dangers.

Oof.

This is a now-extinct predator,

and it would have roamed these parts in the northwest

when the first people arrived in the Americas,

and they actually call it the short-faced bear.

And there is nothing short about this bear.

When it stood on its hind legs,

it would have been about 11, 12 feet tall.

That's about four metres.

And so it would have made the grizzly bear look...

..actually somewhat manageable.

And then look at these teeth, look at these canines.

The stuff that nightmares are made of.

And when it bumped into humans...

..it must have been absolutely terrifying.

And just like those humans,

these bears, too, would have been hungry.

But the early people of the northwest

did not run from the monsters that roamed this land.

Instead, it seems, they went on the offensive.

Signs of their bravery remain in caves along the Canadian coast.

Here, archaeologists sift through the muddy layers of time...

..to find out more about the risks these early people took to survive.

You know when people talk about archaeology? - Yes.

- At the back of a cave, digging mud is...

..is... This is the hard stuff.

- One thing that has been found

in a number of caves on the northwest coast

is, er...spear points in association with bear bones.

- Yeah. - And these date as far back as 13,000 years. - Mm.

So is this one of these spear points?

- This is a fragment of a spear point

that was found in a cave not too far from here. - Yeah.

- We have uncovered a bone in the wall of this unit.

And it's, er, 20 centimetres below the surface.

And, er, so I'm going to pull it and we'll see if it moves. - All right.

And we don't know what species it is or what bit of bone it is?

- Er, there's not enough here to know for sure. - Yeah.

- But it is a pretty big mammal, for certain. - Oh, look at that.

THEY CHUCKLE Oh, it's not ending.

- Just make sure it slides out.

- Ah, it's a rib, isn't it? Is it? - It looks like a rib. - Yeah. - Yeah.

So that could be a bear rib.

It's probably most likely what it is, cos it's quite robust.

- How amazing.

What age do you think it is?

- Well, we have some other samples from above where this bone is. - Yeah.

- And they're coming back, er, around 14,000 years old.

- OK. So it's old. - So it could be the same age or older. - Yeah.

You know, one of the most wonderful things about archaeology

is that sometimes you uncover something

that hasn't seen the light of day in thousands of years.

And in this case, well, maybe 14,000 years.

- Well, we're interested in where bears were hunted in the past.

And in the winter,

when there's... There's not as many resources around

and people are feeling a bit hungry,

knowing where there is a bear den is quite a valuable thing,

cos you can come up there and dispatch the bear.

You'll have a load of meat, fur, as well as bones.

- One theory of how they hunted bears

would have meant getting perilously close.

- Essentially, a hunter would go with a party to a cave,

smoke the bear out of the cave,

and entice that bear to attack a single hunter.

That hunter would be armed with a bracing spear.

A bear would come, er, to take the hunter up in a bear hug,

which is a common thing that they do. - Yeah.

- And the idea is a bear would take that hunter

and cru, er... essentially give him a good crushing.

The hunter, at the same time, would brace the spear on the ground

and aim it at the bear's heart.

And so essentially the bear would take... - Oh...

- ..the hunter and the spear into the bear hug,

thereby spearing itself through the heart.

- A successful bear hunt could have meant food through the winter.

But not every hunter survived.

This is the bone cast of the oldest adult

to have been found along this coast. They were born 10,000 years ago.

And this individual has been given a name - Shuka Kaa.

And there's so much we don't know about this person.

We don't know about their family life.

We don't know if they had children.

But the amazing thing about bones

is that they can tell a story if you know how to read them.

We know that this individual was a male.

We can tell that from various features,

like the squareness here of the chin,

like the back of the mandible,

like the angle here on the pelvis.

On a female, you would typically expect that angle to be much wider.

And it's kind of sad

because you can also tell quite a tragic story on the bones as well.

If you notice here -

that is a puncture wound,

and it fits quite well with the canine of a bear.

And so we think that this individual possibly met their demise

because they were hunting for bears.

The dangers early humans faced down in order to survive

are hard to imagine now.

But their precarious relationship with this unforgiving land

had begun to shift...

..thanks partly to a surprising form of help.

WOLVES CHATTER

By hunting in packs,

wolves can bring down prey far larger than themselves.

A person, especially on their own, would be highly vulnerable.

- Good girl. Yeah.

It's unusual to have them all just around, hey?

OK, come on. Let's go.

- Wolves are, and always have been, wild animals.

Shelley, am I able to come a bit closer? - Yep.

- I think the question is, how close?

It's funny, I can feel it in my shoulders.

My shoulders are a little bit tense.

But, given time, wolves are able to habituate to humans.

Hello.

WHISPERING: Hello.

From around 40,000 years ago, probably in Siberia,

before humans had even reached North America,

the threat they faced from wolves

began to transform into something different.

Now, we're not exactly sure of the details,

but it might have gone something like this.

Wolves would gather around human campsites.

Now, at first, maybe humans were terrified.

Maybe they thought that they wanted to eat them.

But actually, some of those wolves weren't interested in that at all -

they were looking for scraps.

And as they were doing that,

maybe they started fending off other predators

and protecting our combined territory.

And because of this, humans started tolerating

some of the least aggressive, some of the most docile of these.

Maybe they even started feeding them.

We were reshaping wolves into dogs...

..and began to use them...

..to guard our camps...

..hunt prey...

..and pull sleds.

Generation after generation,

we selected the most docile animals and reared their pups...

..driving the evolution of a cooperative behaviour

that suited our needs.

This marked a turning point for the human species.

Living with dogs helped us hunt for food and survive.

It gave us this much-needed edge over hunger,

but it also marked this profound and completely unprecedented shift

in our relationship with nature.

Because never before had any living thing,

whether plant or animal, been domesticated.

This was a complete first.

Unbeknownst to us, we were becoming curators of nature

and gaining more control over our own fate.

But powerful forces far beyond the control of any human

were about to open new gateways into the North American continent.

And as people answered the call of the interior,

far beyond the mountains and glaciers,

they would be forced to find entirely new ways to survive.

A fresh wave of human innovation would be triggered

around 15,000 years ago, when the climate began to warm.

The ice sheets and glaciers started to retreat.

And as they did, the last major barrier

blocking routes into the continent fell.

The first people to enter into the Americas

were coastal people in the northwest,

but it's likely that they eventually travelled

incredibly rapidly down south, all the way to Central America

and then carried on all the way to the tip of South America.

Because remember - they were coastal people.

It's likely that they were using some kind of seafaring method.

So, very early on,

some humans would have started to enter the continent

from along this sea route.

But when the ice sheets eventually started to retreat,

many new routes would have opened up.

More people started travelling into the interior of the country

and finding these completely new landscapes.

Some of the first humans to reach the interior

left traces here in New Mexico.

SLIDE PROJECTOR CLICKS

Fossilised footprints.

Left in the muddy shore of an ancient lake.

The people who made them

may have been part of one of the very earliest waves

of what was to become 10,000 years of human migration inland.

Where there is now desert, they saw rich grasslands.

The fossilised footprints of these continental pioneers

reveal what kind of a world they'd stepped into.

These are the footprints of an actual human being

who stood basically where I'm standing.

And we think she was a female.

And if you look closely at those footprints,

what you see is that, at times, the footprints,

they get broader and they slip a little in the mud.

SLIDE PROJECTOR CLICKS

And that's because

she was carrying a child.

Sometimes on this hip and sometimes on this hip.

Then at other times, she stopped and put the child down,

and you end up with two sets of footprints.

SLIDE PROJECTOR CLICKS

And she walked for at least a kilometre north,

and then heads back south.

I just can't think of anything more...more human

than a mother and a child walking together,

and a mother carrying her child.

And it's interesting, cos this whole journey

has been us tracing the footsteps of our ancient ancestors.

And in a moment like this, that's actually literal.

Archaeologists are finding more of these footprints,

left by a female or possibly an adolescent male carrying a child,

hidden beneath the hard, packed sand.

It's allowing us to piece together an ever more detailed snapshot

of what happened in the moments captured here.

- Let's see if we can define the footprint a little bit. - Yeah.

It's always scary when you start these things.

You've got to...

..take them out.

- There's a subtle difference between the soil in the print...

- It's looser, it's a little damp, so it's going to smear a bit today,

but it will come out.

- You see it so...

..so clearly.

OK. So how have you...? So you've just traced along the...?

- I've just... I've literally just broken the surface

with the dental pick. - Yeah.

- And then this particular example

just brushes out with a little bit of encouragement. - Yeah.

- And you can see the contrast between the white... - Yeah.

- ..and the fill in there. I'm removing the... - Wow.

- ..the sediment that's blown into the footprint.

- So we think she was walking quite quickly, then?

- Yeah, she's walking at about 1.6, something like, metres per second.

- Wow. - And, and a comfortable, normal sort of walk is about 1.3 to 1.5.

So she, she's moving. And this surface is wet, it's slippy.

We do know that this was a mission.

They were on a mission.

They were moving quickly at speed, for whatever reason,

and the footprint, um, tells that story.

- Why that person was hurrying might be explained by evidence nearby.

Other footprints, each one around two feet in diameter...

..left by mammoths.

And crisscrossing the footprints of the mother and child

are the tracks of a giant ground sloth.

Out in the open, with dangerous animals close by,

the mother was perhaps seeking safety for herself and her child.

This landscape would have been filled with mammoth and mastodon

and sabre-toothed cats - just huge animals.

They would have dwarfed us.

The mammoth alone would stand at about four metres high,

that's about 13 feet, at the shoulders,

and the mastodon were only slightly smaller.

For the humans here, this was their new world.

The early people of the plains

would have given these prehistoric mammals...

..a wide berth.

SLIDE PROJECTOR CLICKS

But they must have realised

that those animals also represented opportunity.

That these grazing giants could provide them with food...

..if they could find a way to bring them down.

We know they eventually found a way to do this

because they left a massive clue.

SLIDE PROJECTOR CLICKS

Skeletons of this megafauna.

Some clearly killed by humans.

Humans would have exploited some megafauna,

some large land animals on the coast,

but it was once they hit the interior

that they saw them on a scale like something else,

in terms of their sheer numbers, in terms of their diversity.

But how on earth could people hunt these giants?

BIRD CALLS

CRICKETS CHIRP

One animal still exists which gives us a sense

of just how difficult that would have been.

RUMBLING

HOOFBEATS RUMBLE

This beast can sprint at up to 40mph.

The male's horns are over two feet long.

And, 14,000 years ago,

these bison had an even bigger prehistoric relative

roaming these parts.

WHISPERING: Absolutely incredible, but they're also so...

..big. They're about one tonne in size.

And the giant bison, the one that's now extinct,

but would have been around back then,

was up to 50... 50% bigger.

HOOFBEATS RUMBLE, BISON SNORT

It's one of those things, I think -

today, you can romanticise the idea of these hunts

and you think about them as some kind of,

you know, adrenaline-filled adventure,

but it's harder to grasp that, actually, back then,

it would have been filled with fear and risk.

Only a powerful spear thrust could penetrate the giants' hides...

..so hunters needed to get close.

ALARM CALL

Many hunts ended in failure.

They needed a technology upgrade.

Up until this time,

the way spear points were attached to their shafts

was a serious weakness.

SLIDE PROJECTOR CLICKS

Spear points frequently broke on impact...

..until the design was altered.

A subtle shift at first glance,

but one that would change everything.

This is special.

So, it's about 18 centimetres long.

It's pretty sharp.

If we look at the shape,

it's long and narrow with the broadest point being quite low down.

Notice also this thinning here compared to the middle.

It's thought that the shape might help with the penetration of hide,

and it's thought that this might help

with reducing shattering on impact.

We call it a Clovis point,

because it was found near Clovis in New Mexico.

The narrow base of the Clovis points

allowed them to be slotted firmly into the spear shaft,

better absorbing the force of impact.

From archaeological finds,

we know this new design rapidly spread across the continent...

..and the technology continued to develop.

Within 500 years, these points had evolved

into more slender and sharper forms...

..able to penetrate deeper into prey...

..and archaeologists think these spear points

were delivered with such lethal force

because of another piece of technology...

..whose use was exploding.

So this is a replica spearhead,

and it's been hafted or attached on to a wooden shaft.

So, this would have been quite an effective weapon,

but this is where technology gets really interesting

because it's thought that one of the ways that they threw these spears

is with a spear thrower.

So you'd attach it to the top here,

and then you would effectively use it to...

..propel the spear forward.

At that velocity, you're more likely to pierce the hide of an animal.

And to me, it's...

It's especially interesting because what you get with this

is the ability for female hunters to be more effective,

because suddenly it's not just about strength, it's also about skill.

The new hunting technologies

allowed people to take down the largest animals in their world.

Humans had become the apex predator of the plains,

and now feasted on a glut of meat.

Our hunting prowess was shaping society here.

This is absolutely stunning.

It's one of the most striking spearheads I've ever seen.

It's... It's so well-crafted, and it shines,

and it looks like it was made of glass -

but actually, it's made of quartz,

so it's incredibly strong and it's sharp,

and yet it doesn't have any signs that it was actually ever used,

and that, along with the fact that it's so beautiful,

suggests that it was ceremonial.

Now, when you've got an everyday object

and it's made to look so... so beautiful, and so striking,

it implies that it had become a symbol.

We're not sure of what - perhaps of how important hunting was,

but perhaps of a cultural identity, perhaps of who they were.

Feasts began to bring different communities together...

..and cement social ties.

Sharing meat fostered cooperation.

Food was fuelling a culture.

In the midst of this abundance,

it must have felt as if it would go on forever.

But their world was changing.

The end of the Ice Age

that had gifted them this warm world of plenty

was now beginning to have an effect they could not have foreseen.

It's thought that melting ice at the poles disrupted ocean currents.

Temperatures in the northern hemisphere

rapidly cooled by several degrees.

Across North America,

the vegetation had begun to alter in unpredictable ways.

In some areas, trees and shrubs

began to replace grassland and tundra.

SLIDE PROJECTOR CLICKS

Woolly mammoths could not effectively chew or digest

these woodier plants...

..and as their environment transformed...

..the giant herbivores dwindled.

Over the space of just a few hundred years,

three-quarters of the large animal species in North America

became extinct, vanishing forever.

I imagine it must have been a shock for the early people here

to witness the megafauna disappearing,

because that's what they would have seen -

and they're such a part of your culture and your diet

and your lifestyle, and suddenly they're not.

That... That must have been quite difficult to comprehend.

Now, the main cause of the giant megafaunal extinction

is climate change, but it's likely that human hunting played a role,

that it was this final nail in the coffin -

and so, perhaps unknowingly, we humans tipped the balance of nature.

The once bountiful land of giants

had become a pile of bones.

All the hunting technology in the world

could do nothing to reverse this catastrophe.

The people here were plunged back to a time before the feasts.

With these animals gone, how would they now find enough food?

A clue lies in ancient holes carved in the rock.

People needed to branch out

and exploit every part of the food chain,

all the way through to something you probably don't think of as food -

and that's acorns.

Now, these are incredibly bitter because they're full of tannic acid,

and to get rid of some of that,

what they would do is they would firstly get rid of the shells,

and then they would grind the nuts up

with water in the hopes of getting rid of some of that bitterness.

And...honestly, acorns sound disgusting

and they taste disgusting.

They're still incredibly bitter -

and yet it's likely that the flour from these and the paste from these

were some of the earliest processed plant food.

We actually have some of the grinding stones

preserved in the archaeological record -

and if you look at all this, it seems so clever,

it seems so inventive,

and yet it's a lot of effort to go to

for what are essentially some really unpleasant calories.

If you were starving, no question you'd do this...

..and with the loss of the megafauna,

people's survival now hinged on smaller game

and foraging for plants.

But there had to be another way.

The solution people came up with in the Americas

would be found in tropical forests to the south.

This place, it has...

It has real challenges.

There are plants - so many of them look edible,

and yet some of them are definitely poisonous.

It requires a process of trial and error to find the actual food.

It was in a forest, archaeologists think in present-day Mexico,

that a momentous change took place -

and it began with the simplest of actions.

Every so often, someone would have come across a plant

that was safe to eat,

and would have sought out more of it.

An example of this is this grass called teosinte.

Now the seeds are incredibly small and hard,

but they can be ground up into an edible flour.

So, that same ingenuity that humans brought to acorns,

they were now bringing to this grass.

Where people found teosinte growing,

they encouraged it by weeding out other plants...

..and collected the seeds for food.

This may have continued for centuries...

..until one individual would have become the first person

in the Americas to do something completely original

with a teosinte seed.

There is something so magical about planting a seed, watering it,

and hoping that it sprouts

and becomes a tiny little delicate green shoot.

And there would have been somebody

who planted the very, very first seed...

..and they would have - they would have known

that it would require effort and care

and protection from herbivores

if it was to ever become something big enough

to feed their families with.

And anybody who's ever had an allotment, or a garden,

or a balcony knows how much care and commitment goes into it.

This was an idea whose time had come.

Because humans all over the planet started to plant seeds

and grow them for food...

..and it was an experiment that began to pay off.

Because across the world, the people who did this

were creating a more dependable way of feeding their families,

and so triggered a pivotal moment for our species.

In different places all over the Earth,

humans were inventing farming.

Probably first around 10,000 years ago,

in the Fertile Crescent of the Middle East,

where we domesticated wheat...

..then rice in China...

..sugar cane in present-day New Guinea.

Farming emerged independently

in separate locations across the globe...

..Central and South America among the first.

Here, people created what would become

one of the three most important staple crops

for feeding the world...

..because as the early farmers planted and harvested teosinte...

..they began to shape it into a new kind of plant.

Every so often, a genetic mutation would arise in teosinte

that would actually be quite beneficial for humans -

that would give rise to, say, larger seeds,

or more seeds, or sweeter seeds -

and, perhaps most important of all,

would get rid of the hard seed covering,

and humans started selecting for these better varieties,

and over thousands of years, they created something new,

that looked very different from teosinte -

because they created maize.

It was no longer a wild plant.

It was now a domesticated crop.

The invention of farming was to set in motion a change

that would go far beyond how we fed ourselves.

The clue is in that word, "plant" - to be put down in one place -

and just like the plants that they grew,

those early farmers would have had to have adopted

a very similar lifestyle.

Because you couldn't exactly keep moving

if you had to tend to your crops,

and so, for the very first time since the birth of Homo sapiens,

we were no longer a completely nomadic species.

More and more of us were quite literally putting down roots.

Farming supercharged our capacity to fuel human activity...

..and what emerged was extraordinary.

Here in South America,

there's a place where they began a new way of living

on an unprecedented scale.

The stepped pyramids of Caral were once lost under the desert sand.

Archaeologists are now uncovering a vast complex of structures.

And what made it possible to build these extraordinary edifices...

..were the fields of crops that surrounded them.

Caral became an immense hub for trading food.

It represented a new path humans could take

towards permanence and stability...

..but for our species to choose that path

was not a foregone conclusion.

I just can't help but think,

what would it have been like

for people visiting it for the first time back then?

Because they would have never seen a city before.

It must have been so alien to them.

It must have looked like a place from a different world.

This was a commitment to a static way of life -

and yet we don't consider how tumultuous

the process might have been,

how much social upheaval might have been involved -

because for those who chose to lead this life,

it must have come with a huge cultural shift,

because humans were becoming an urban species

for the very first time.

Humans across the planet stood at a fork in the road.

For almost 300,000 years,

we had survived as nomadic hunter-gatherers...

..but settled lives as farmers

promised a more reliable way to feed ourselves

and plan for the future.

The choice most of our species took

would bring dilemmas and dangers we could never have imagined.

In the final chapter of our Human story,

we begin to live together in ever larger numbers -

but open a Pandora's box...

..of death and chaos...

..as we seek ways to harness human knowledge

on our path to the modern world.

In this episode, we filmed at a place I'd long dreamt of visiting.

White Sands in New Mexico.

Underneath the surface of the desert are sets of fossilised footprints.

They've become the subject of some of the most ground-breaking

but also most hotly debated research in archaeology.

In 2018, the discovery of the double footprints,

possibly a mother and child,

revealed vivid details about who the early people here were...

..and what animals roamed alongside them.

- When we first started seeing the human prints

walking alongside a mammoth print,

when I'd first seen it, I was like, "Uh, that's not possible,"

but it takes a while to understand what you see,

and then you go back and you start to understand them.

- But the prints themselves were just the start -

because, in 2021, new research on their age

sent shock waves through the scientific world.

- There's been a lot of ideas when people got to the Americas.

Some of the main theories is there's a large ice sheet

and people weren't really able to enter this area

until about 14,000 years ago, until that ice sheet melted.

- When humans first arrived in North America,

an ice sheet covered the northern half of the continent.

If no humans had been able to penetrate the interior

until it had melted,

then the oldest the footprints could possibly be is around 14,000 years -

but the dating of the footprints

seemed to overturn that conventional view.

- We put in a trench at the edge of the lakeshore

and we're finding prints

that were dated above and below the prints,

so we can see the soil chronology.

- The footprints themselves can't be carbon dated -

but fossilised plant seeds

trapped in the mud near the footprints can be,

and carbon dating of seeds

in the layers above and below these footprints were explosive.

- So, we don't know exactly how old they are,

but we're looking at the lake sediments,

and what we see is there's at least 11 different layers right now,

and those range from the top of the sediment to the bottom,

from 21,000 to 23,000 years old.

- The dating research suggested the footprints

went as far back as 23,000 years ago.

If true, it would mean humans had set foot in North America

thousands of years earlier than many scientists had long believed.

- So, at White Sands we see people here

before the last glacier maximum,

before there was these last ice sheets,

people were already here.

- The very early dates are controversial.

Further research will be needed

to confirm how old the White Sands footprints truly are.

If they date to before the melting of the ice sheets,

did those pioneers travel around the ice?

Despite the debate,

the footprints remain one of the most important archaeological finds

of recent history,

with huge significance for the entire question

of when humans first set foot in the Americas.

Around 300,000 years ago,

our species, Homo sapiens,

evolved in Africa.

For generations,

small bands of hunter-gatherers explored the planet...

..learning to survive.

Many other species of human walked the Earth alongside us,

but one by one, we supplanted them...

..until only we remained.

For most of our history, our population was tiny and fragile.

Every aspect of our lives determined by the natural world.

And yet...

..everything would change.

Today, there are about eight billion of us,

most of us living in cities, like this one,

able to connect in an instant with people across the planet.

And you might think it was inevitable,

the result of progress over time, but surely, our story so far, if it

teaches us anything, it's that none of this was a foregone conclusion.

So, how did we get here?

How did humanity transform from scattered

groups of nomads into our modern, interconnected world?

What happened in that final chapter of our story

that took us on a path to this place?

On a remote hilltop, in the far east of Turkey...

..stands a prehistoric monument steeped in mystery.

It is so hard to stand here and not have goose bumps.

This is the oldest temple unearthed anywhere on this planet.

It was built 11,500 years ago by hunter-gatherers.

That's 6,000 years earlier than Stonehenge,

and yet somehow, our ancestors were capable of making this.

This is Gobekli Tepe.

There are these incredible T-shaped pillars,

which would've been holding up a huge roof.

And then, if we look at them, they're covered in these engravings.

So, this is a fox, there's vultures here, there's bear,

there's wild boar, and here, this one just has to be my favourite.

It's a leopard, hunting one of those wild boars.

So, notice these holes here.

This was dressed with furs and they were also painted.

So, you get the impression of this place as being beautifully

coloured and textured.

And yet, this incredible feat of architecture is not the most

revolutionary thing about this place.

Gobekli Tepe is not simply a temple.

It is a marker of a species on the cusp of change.

In many ways,

these prehistoric builders lived as their ancestors had for thousands

of years, their days spent foraging and hunting to feed their families.

ANIMAL GRUNTS

But they'd made one fundamental change.

After generations spent as nomads, following the herds...

..here at Gobekli Tepe, they stopped moving and settled down.

The evidence for which lies not in the temple itself...

..but in the rubble surrounding it.

Now, this might not look like much compared to that,

but this small square building is actually

the remains of one of the first permanent houses ever built.

That there is a storage vessel, this is a grinding stone for wild

wheat, and this floor of plaster and stone, this was somebody's home.

This is one of the first villages.

Archaeologists believe maybe a few hundred people

were living here permanently...

..and calling it home.

For 300,000 years, Homo sapiens roamed freely.

But now, they were gathering together to put down roots.

And so, the question is, why?

And why now?

This was a world of plenty...

..warm and abundant.

But the planet had not always been this way.

Only a few generations earlier, Homo sapiens had been

fighting for survival...

..through the brutal peak of the last Ice Age.

Now that local areas could provide plenty of food,

people could spend longer in one place,

and when large groups came together to share their bounty, a feature

of our brain had an opportunity to flourish like never before.

Our almost limitless capacity to learn.

An ability with roots that can be traced way back,

right to the beginning of the human story.

As the distant ancestors of our species were gradually evolving...

..they had begun developing larger brains.

But as their brains grew,

the way they were organised was evolving too...

..becoming increasingly adaptable, and more able to

change in response to stimulation from the outside world...

..until they became us...

..a species brilliant at learning,

both from our experiences and other people.

The major thing that marks our species as different isn't

just the size of our brain, it's also the way they're organised

and their extraordinary flexibility.

Now, we call this flexibility neuroplasticity,

because it's like our brains are plastic.

They adapt, they alter and they change.

It has some profound effects.

Humans have a natural affinity for observing

and copying each other...

..giving Homo sapiens the ability to have a

shared understanding of the world.

At Gobekli Tepe, the symbols of their shared experiences

and beliefs are carved into the stone.

And these indicate a bigger shift in our species.

The odd thing about being human is that we are constantly

surrounded by a bunch of things that are so all-encompassing, and yet we

never really think about where they started or where they come from.

I'm talking here about culture.

Ritual, custom, language, art, stories

and ideas that have been passed down orally through generations,

and have now found physical form.

Places like Gobekli Tepe became so rich in meaning

that our ancestors never wanted to leave, and culture flourished.

Cooperating and building connections

are what our brains are actually set up to do.

Wherever humans settled down, an explosion in creativity

followed, launching an era of extraordinary innovation.

We can see the results of this shift in the archaeological record...

..which begins to seethe with the debris of new technology.

Our ancestors couldn't have foreseen it,

but one innovation from around this time was to have consequences

far greater than they could possibly have imagined.

We start to see the first sparks of something that would come to

shape the way we live today.

Wherever there were humans, there was

a dramatic rise in the bones of goats and sheep...

..far outstripping the remains of the species they hunted.

These changes reveal a key point in the human story...

..the moment we began to farm livestock.

The people had found a safe, reliable way to feed themselves.

They'd stopped chasing their food and started rearing it...

..providing a regular supply of milk, cheese and yoghurt...

..and later, textiles like wool...

..season after season.

The farming of animals marked a watershed moment.

The result of this, I don't think could've been predicted.

This altered relationship that they had with animals, altered them,

because not long after they learnt how to do this,

something fascinating happened.

Their population started to boom.

Now, we're not really sure why this happened,

but the strongest theory is that people staying in one place

and not moving as much, but also having more food, having more

calories, basically led to mums having more energy for reproduction.

As our numbers rose, settlements began springing up...

..scattered across an area which we now call the Fertile Crescent.

As their populations grew, villages transformed into towns.

And the largest of the towns of the Fertile Crescent was Catalhoyuk.

An early prototype of urban living.

Wow!

Every single one of these is a house.

- That's right. And you have to imagine, of course,

that each of these houses is a box, with a roof.

But, uh, there's no space really between them.

Like a beehive.

The fact that they're all tightly up against each other means

that the whole thing is much more structurally sound.

- There's literally no gap.

- The only way you can get in the house is to move along the roofs

and go down through a hole into the house,

because there's no streets.

- Each dwelling was small and had its door in the ceiling.

The inhabitants lived much of their lives up on the roofs...

..grinding grain, trading,

and feasting in the bright sunlight above their homes.

In this honeycomb,

their animals were kept in pens right next to the living quarters.

- Here, you can see bits of animal bone. These are the sheep bones

from feasting and so on.

But also, there are lots of droppings

and so, this is telling us that, as well as people

living in the village, they also brought in domesticated animals.

- And these farmers left behind intriguing signs

that they were here to stay.

What are those holes over there?

- These are the ancestors who are buried beneath the floors.

In some houses, there are up to 62 people buried in them.

- I mean, Ian, 60-odd people being buried,

that's a graveyard in a home.

- We've dug up hundreds of burials here,

and what's fascinating is that people were sleeping just

a few centimetres from the bones of their ancestors.

- Between the dead, the living and their animals...

..this thriving town was densely packed.

At its height, some people think there were 8,000 people

living at Catalhoyuk, so that's one of the largest

settlements on the planet at this point.

And so, it's so easy to imagine this straight line from this

population boom to our own huge population of humans on this planet.

And yet, that straight line was severely interrupted,

because the formula for success that was playing out here

also turned out to be a bit of a disaster.

Our pioneering farmer ancestors couldn't have known it...

..but they had opened Pandora's box.

Amongst the many burials of Catalhoyuk...

..were skull after skull with clear signs of violent impact.

And it's something not only seen at Catalhoyuk.

In many early farming settlements,

we start to see the unmistakable signs of violence...

..suggesting the two are connected.

Choosing to live like this, in such close proximity with your

neighbours, with the animals which you're breeding,

with your rubbish...

..in a way that has never been seen before, leads to this cascade.

The densely populated towns had become exposed to new dangers.

Living with their animals spread disease.

Their dependence on crops made them vulnerable to failed harvests.

And with ever growing competition for the land near the settlement,

people were no longer just battling nature,

they were battling each other.

Suddenly, it must have seemed like this perfect world

they'd created was cursed.

Faced with all these challenges,

these towns didn't survive or grow into great metropolises.

Instead, growth was followed by collapse and exodus.

And as the early town dwellers left their homes

and farms in droves, they faced a choice.

To start again and risk failing, or rejoin the vast

majority of humans across the globe still living nomadic lives.

For me, this is one of the biggest mysteries

in the history of our species.

Because for the very first settlers, it was a disaster.

They were facing disease and famine, and yet, at the very same time,

across the planet, hunter-gatherers were thriving.

And that way of life we know works,

because today, millions of people live like that.

They have made it to the 21st century just like the rest of us.

And yet, we know how this story ends.

Most of us live in huge cities like this.

So, what is it that turned a disaster into a success?

Our early attempts to live together in large numbers

had ended in failure and strife.

To make it work, our species would have to find another way.

An answer would lie...

..along a great river.

There are bits of our story where geography just does not

feel like a fluke. Where if it was going to happen,

it was always going to happen here.

Because beyond the thin strips of green that cut through this

arid landscape, there is very little but sand and death.

This narrow strip of habitable land was the only place to grow food

and rear animals.

But to produce enough, they had to control this natural resource.

The people needed to direct the water onto their fields,

and harvest en masse, once a year.

And so, they had no choice but to work together.

Put enough effort in, and more and more of this becomes

productive farmland, giving these guys a massive food surplus

that would be collected in huge grain stores, attracting more and

more people to come and settle here, and join this growing revolution.

The people flooded into the Nile Valley, jostling for space.

But now, instead of abandoning their communities

when the towns became overcrowded...

..they restructured them.

When you live in a small group, you've all got to be good,

or at least competent, at everything to survive.

But living in a large group, you can suddenly specialise.

Some of you might become really good at a particular

kind of textile making.

Others might become stone makers, butchers, bakers,

probably not candlestick makers yet.

All cogs in a huge machine,

at a scale that had never been seen before.

The people of these busy settlements were increasingly collaborating.

Becoming part of a social group

with hundreds or thousands of strangers.

And in the process, laying the foundation for something brand-new.

I know archaeologists are constantly pointing at walls

and trying to convince people of how important they are,

but this absolutely massive wall is pretty much all that's

left of the original city of Abydos.

Abydos being one of the very first cities in the whole world.

But walls like these also indicate a momentous shift

in the way humans lived together,

because to be on this side of the wall meant protection

and access to the grain stores,

but to be on that side of the wall meant to literally be without.

Now, humans have always been tribal, we've always been able to act

and think as part of a group, but what places like this prove

is that tribalism was scalable to the size of a city.

All along the great rivers of the ancient world, huge cities began

to appear, as our ancestors cracked the secret to living at scale.

A change which would propel us forward at an astonishing rate.

As these newly emerging cities grew

and their communities became more complex...

..they started to change...

..leaving evidence which can still be seen here in Abydos.

Not in the city of the living, but in the city of the dead.

This is Shunet El Zebib, and it's so vast, clearly,

but it was actually originally mistaken for a fort.

But it's a temple dedicated to a human, a man called Khasekhemwy,

who's actually buried in a cemetery over there.

Not everybody got one of these, which means that around here,

there were now at least two classes of people.

There was something about cities that was the perfect breeding

ground for producing not just the haves, but the have-a-lots.

We may never know why some people became wealthier

and more powerful than others.

One theory is that those in control of the water

could also be in control of the food supply.

But so long as they shared enough to feed the cities, the cities thrived.

Their newly specialised populations invented, made

and traded an unprecedented number of objects.

And in the process, created a tool, unassuming at first glance,

that would become a powerful instrument.

I know they don't look like much.

They look like just square pieces of bone.

They were found in Abydos, in a tomb, thought to be that

of a king known as The Scorpion King, from about 5,300 years ago.

Now, some of these symbols are very recognisable.

That's obviously a bird.

This is a plant of some kind.

And notice the holes in them.

These are effectively labels, or tags.

These tags were thought to have been attached to offerings

buried in the tomb, but what they reveal is something

happening in the world of the living.

And these symbols represented the provenance where the

item that they were attached to came from.

Perhaps they have a quantity as well attached to them.

And then someone had this absolutely revolutionary idea.

What if they strung them together?

With local agreement on their meaning, symbols became words.

Gradually, the rows of images became more complex...

..until...

..we stopped labelling and started writing.

Detailed knowledge and culture that had previously been

passed down generation to generation to generation was now able to

be preserved in a completely different way.

And the thing with writing is that like

so many of the giant leaps forward that we have made as a species, I'm

thinking here about the invention of agriculture and metalworks

and the wheel, writing does seem like an idea whose time had come,

because it doesn't just happen in Egypt.

Again and again across the Earth,

we invented forms of writing.

Giving our facts, stories and ideas lasting form.

And we still have no conclusive evidence as to how or even

whether these events influenced each other, or

whether they happened organically,

as a result of needing to keep track of things at that scale.

But however it happened, once writing was a thing, once it was

out there in the world, then nothing would be the same ever again.

Now, laws, customs

and beliefs could be recorded permanently in ink.

But with over 700 symbols,

this technology required years of study to master...

..and so was the sole preserve of those trained to use it,

scribes working for the ruling class.

And the ability to send out detailed instructions to people across the

land gave the rulers enormous power to influence, instruct and build.

In 2013, a team of archaeologists were excavating

a cave on the Red Sea coast...

..when, hidden inside,

they found ancient fragments of inscribed papyrus.

Preserved there for over 4,000 years.

It's believed to be the oldest ever found.

And a time capsule from the reign of an iconic ruler.

So, this is...this is your actual excavation notebook from the time?

- Yeah, yeah. Every day, I was recording the papyri,

and we were surprised to find most of them have the name of a king.

And this pharaoh is Khufu, the builder of the Great Pyramid.

- Not a small pharaoh.

- All the material is giving information about this very

reign, which is the very beginning of the Egyptian state, in fact.

- Yeah.

Khufu ruled Egypt for almost a quarter of a century.

And one of world's most familiar structures was built to

honour him - the first of the Great Pyramids of Giza.

- We had to wait till the very end of the excavation

to have the best-preserved papyri.

We only had a small piece left untouched. - No!

- And all the papyri were thrown inside...

- Into that one spot that was the very last spot

that you decided to look in. - Yeah, yeah.

- The team discovered around 1,000 pieces of papyrus,

revealing a vastly complex construction project.

Wow! - Yeah.

It belongs to a kind of elite at that time,

because we don't think that more

than 1% of the...of the population was able to read and write.

It's a logbook, and I can see in the small boxes

the number of the day of the month, and for each day,

this official is giving information about what he has done.

For example, here, on the first day of the month, they are

sending a boat to Heliopolis, to fetch the food for the workers.

And when it arrives, it's written in red,

because it's much more important for them than everything else.

About 40 days, you have a precise record of what he is doing.

Egyptian extracted fine limestone blocks that were used

for the building of the outer casing of the pyramids.

So, what it is all about is that they were bringing

stones from the Tura quarries to the pyramid of Khufu at the end

of the reign of this king.

- So, this is...this is telling us how they built the pyramids, basically.

- Yeah, basically, yeah. - This is the administration behind it all.

That... That's absolutely incredible.

So, this is a snapshot in time

of the building of the Great Pyramid.

- Mm. - And you found it.

- Without all those records, I think

the pyramid would not have been possible.

- You can't really overstate the significance of finding

a document like that, one from such a pivotal moment in history.

And when you read the translation, you definitely do get

a sense of what a logistical feat it was,

building these things.

But you do also get a real sense of how mundane

and bureaucratic it all was.

Just kind of ordinary humans doing ordinary human things.

Between the invention of writing and the building of the pyramids,

there were no major technological advancements

that we know of in Egypt.

And so, for 4,500 years, people have looked at these and just had their

breath taken away, and wondered how on earth were they built.

And perhaps the answer is just this simple - writing built the pyramids.

And even though they were originally built for the elites,

they actually became symbols of national identity,

which bind huge groups of people together on an unconscious level.

The unit of human cooperation had grown from tribe, to village,

to town, to city...

..and now, to nation.

But alongside the emergence of these nation states

was a more sinister development.

What had once been tribal skirmishes became state warfare...

..recorded by the victors in art and writing.

The emerging superpowers began launching military

campaigns against their neighbours, for land, resources and manpower.

Bringing thousands of captives back as slaves.

Many of the early civilisations follow this pattern of growth,

innovation, writing and an ever more stratified society.

By 4,000 years ago, we'd clearly made some massive strides to the

modern world, with the rise of these civilisations that were supporting

so many more people, and about 70 million of us walking this planet.

But...

..the disparity in the human condition had never been so wide.

Some people were living gods, and they would go on to build

monuments like these to themselves for centuries.

But many more were slaves, who were forced to

live in the shadows of the splendour that they'd helped to create.

And humankind's powerful new tool, writing...

..still remained in the hands of just a tiny number.

If we were going to get to the future, the here and now as you

and I know it, it was going to require a spark from somewhere else.

Almost 4,000 years ago, a small group of our ancestors were

forced to make a journey to one of the most inhospitable

places on Earth.

Through the baking, barren waste

of the Sinai Desert.

But here, in this desolate landscape,

they would change the world.

This place is stunning and yet, a complete and utter deathtrap.

It was of very little interest to the Egyptian elites.

That is until someone found something in these mountains.

Lots and lots of copper.

And this stuff, turquoise.

Raw materials that could be transformed into jewels

and ornaments of great value...

..if you could prize them from this harsh landscape.

Far to the north was the tiny land of Retjenu.

When Egypt demanded labourers for this treacherous mining mission...

..it was the unfortunate people of this small powerless state,

who had no choice but to answer the call.

I can't imagine what it would've been like to be dragged here

to work in the turquoise mines, in the blazing heat,

in the middle of nowhere.

It must've been like being dropped onto

the surface of a different planet.

And even the Egyptians probably wondered

if they would make it back home.

The Egyptians turned to their gods for protection.

And here, high up on a desolate plateau,

at the furthest edge of their world, they built a temple to ask for it.

A monument which has survived remarkably

unscathed for almost 4,000 years.

Frozen in time by the bone-dry desert.

This temple is dedicated to the goddess Hathor,

who is the goddess of turquoise and miners.

And they were documenting and celebrating their presence,

and worshipping their gods.

And each one of these pillars represents one of the missions.

And they are hierarchical.

So, you've got the Pharaoh at the top, and it goes through the ranks.

You've got stonemasons, etc, etc, etc,

until this is the brother of the Prince of Retjenu.

Retjenu is where the miners came from.

And yet, the miners are not here on this pillar, but they would have

come through here, they would've seen this grandeur, this splendour.

Seeing these impenetrable Egyptian hieroglyphics...

..the foreign workers also wanted to immortalise their presence here.

But there was a problem.

They weren't part of the elites and so they couldn't write.

So, the illiterate miners did what we humans have always done.

They copied what they'd seen and made it their own.

This is one of the turquoise mines, and if you look, all over the walls

there are these scratches from where the workers' pickaxes have been.

But here, something else is going on.

There are about 30 or 40 of them all over this place.

Some of these have been copied from hieroglyphics,

but some are completely new, and here's how the system works.

You take the symbol and you say the name,

but you only take the first sound, and you discard the rest.

So, for example, this here.

This is an ox, you can see the horns and the head here.

To the miners, this would be "aleph".

Now, aleph, just take the first sound, "a", discard the rest.

This is another symbol. This is the symbol for house.

To them it would be "bet",

so you just take the "be" sound at the beginning.

And if you put these two together,

you start understanding what you're actually looking at here.

This is the birthplace of the alphabet.

This new script was simpler to learn than hieroglyphics, because

the alphabet did not represent complete words, but spoken sounds.

It was able to convey any thought with only 20 to 30 symbols.

These miners are the ones who gave birth to this,

and their legacy is still with us today, and is so important.

In the centuries and millennia that followed...

..nearly all the early written languages

fell into obscurity as those civilisations waned.

But the alphabet would only grow, spreading across the planet,

reshaping and branching into many different forms.

Eventually becoming the most wildly used writing system

in the world.

Allowing millions, and then billions, of ordinary humans

to access knowledge, to communicate and to document their thoughts,

and their existence, in every corner of the globe.

For me, this is one of the most powerful moments in the human story,

because unbeknownst to the underdog, they had changed the world.

One of civilisation's most profound and revolutionary ideas didn't

come from an educated elite, it came from inside these dark and miserable

mines, through the copying and innovating of lowly migrant workers.

The invention of writing marks an ending and a beginning.

Because prehistory, so the period before writing,

we could only really piece together using fragments and artefacts,

and now recorded time, history, had begun.

And what we see is that as writing spreads,

the pace of human innovation accelerates.

Because that is the power of being able to document

and lay down knowledge.

Generation after generation building on the last, retaining

and accumulating knowledge.

Stone became bronze, iron became silicon...

..and gradually, we built the future.

This is the very final bone of our series.

This is actually one of the three ear bones,

and just like every human bone we've encountered,

whether Homo sapiens or otherwise, it represents a person.

This individual had a family, parents, perhaps children, friends.

But what's particularly remarkable is how much

we now know about these ancient ancestors of ours,

thanks to modern temples of knowledge, like this one.

The scientists here are able to extract DNA from an individual

who, in this case, lived about 1,600 years ago,

from a piece of bone that is so tiny, delicate and precious,

and they're able to ask questions, like whether industrialisation and

agriculture actually affected our DNA, whether we're still evolving.

And to think that our knowledge has got to the point where we're

even able to entertain such huge questions

from something so tiny...

..for me there's a poetry in that.

We can look back on when nature and luck were on our side...

..and when they weren't.

Where we made the right decisions...

..and where we went wrong.

But what underpins our story

and makes it unique is far more than just our will to survive.

It's our cultural drive to come together, to learn from

and inspire each other, to go further than what has gone before.

We are the very last species of human to walk this Earth,

and the most fascinating thing about our 300,000-year-long story

is that we have no idea how much is left.

Is this basically the whole of our story, or are we on the first

act, or even prologue, with a long future ahead of us?

We have no idea.

But we are one species with one future.

Now, you could never have predicted how we got here,

and where we go next is up to all of us.

In this episode, we filmed at Serabit el-Khadim,

a 4,000-year-old mining complex on the Sinai Peninsula.

Where ancient messages were scrolled on the walls of the mines.

The archaeologists who discovered this mystery script in 1905

called it Proto-Sinaitic, but they had no idea what it said.

And until they could read it,

they were ignorant of its true significance.

A remarkable artefact, now in the British Museum, would be

the vital clue to cracking the ancient code.

- This amazing object was discovered in the Hathor

temple in Serabit el-Khadim, close to the turquoise mines.

It's a so-called sphinx and dates roughly about 4,000 years old.

- Linguists already knew how to read ancient Egyptian hieroglyphics.

What the sphynx gave them was a key to decipher

the script they couldn't read.

- So, if you look at the piece, we have inscription on both sides,

and I'll show you this side first,

where we only have the Proto-Sinaitic script.

And then if I turn the sphynx, this is the most important and most

fascinating side, because here we have then two different scripts.

On the bottom, Proto-Sinaitic,

and then you see the hieroglyphic right on top.

- The message in hieroglyphics at the top was a dedication

to the goddess Hathor.

Linguists deduced that the script below in Proto-Sinaitic

was saying the same thing.

- We can start with the hieroglyphs, which reads "Beloved of Hathor",

so we have now the Egyptian goddess Hathor.

Then we have a second part, which allowed us to decipher

the Proto-Sinaitic language, because we know it was the same message.

So, we were very lucky we found this amazing object.

This is the kind of lottery win for the linguists.

- These short, corresponding phrases were the key to decoding

the miners' writing.

- The probably most important aspect of Proto-Sinaitic is that

it's an alphabetic script, and if you look at these signs,

you probably will not recognise any alphabetic signs we use today,

but the cow head that you see here becomes our A.

- Proto-Sinaitic gave birth to the modern alphabet, and unlocked

the origins of the most widespread form of writing in the world.