All language subtitles for auf S01E10 - Copie

[narrator] revolutionary microbiology

Investigates the medieval undead.

[sheila hoffman] placing
the stone in the child's mouth

Was to prevent them from
coming back to plague the living.

[narrator] chemical fingerprinting,

Decodes a roman terror weapon.

Hundreds of these
sling bullets raining down.

It would scare the daylights out of anyone.

[narrator] genetics helped
trace the new human species

Responsible for stunningly
sophisticated jewelry.

It doesn't make any sense.
Who was using these techniques

Tens of thousands of years ago?

[narrator] in a digital
technology lab of the future,

Experts uncover clues
invisible to the naked eye.

I've never seen anything like that before.

[narrator] and solve mysteries
that have baffled for centuries.

That right there is what
scientists have been missing.

All the evidence points
to an incredible discovery.

This could be a game changer.

[narrator] state of the
art digital technology

Closes the toughest cases.

This mystery finally makes sense.

[narrator] from the
ancient unexplained files.

[narrator] mt. Llullaillaco, argentina.

1999.

Near the summit of the world's
second highest active volcano,

Archeologists find three
mummies in pit tombs.

It's an extraordinary
setting. A towering volcano,

Containing three small figures.

They're frozen stiff by
the frigid mountain climate.

A natural mummification.

The level of preservation is astonishing.

It's like they almost died yesterday.

The scene is unbelievably eerie.

There's no obvious
wounds or a cause of death.

The circumstances are really bizarre.

[narrator] over the next decade,

A battery of science and high tech

Pieces together these children's stories,

To reveal how they met their chilling end.

An extraordinary amount of
effort must've been put into

Placing these children
here up on this mountain.

22,000 feet above sea level.

How did they end up
entombed in this remote volcano

Hundreds of miles from civilization.

[narrator] this baffling
discovery makes mt. Llullaillaco

The world's highest archeological site.

Analysis of the three tiny figures

Shows the oldest is a 13-year-old female.

She's given the name, maiden.

Accompanying her is a
younger boy and a girl.

She displays horrific facial burning.

[karen bellinger] the girl's
ear has been melted off.

It looks as if she's been struck
by lightning right in her grave.

In fact, researchers
call her the lightning girl.

[narrator] alongside these victims
is a stunning array of grave goods.

Including gold and silver
figurines, fine pottery

And exquisite textiles.

All protentional clues to their deaths.

It has all the hallmarks
of a ritualistic burial.

But why build these tombs
at these dizzying altitudes.

It's deeply mystifying.

[narrator] first, samples from
the children are radiocarbon dated

To determine which culture they came from.

A sample of the maiden's hair
dates to the middle of the inca empire.

So that helps shed
some light on this mystery.

This leads us away from
some kind of burial custom

And more toward sacrifice.

[narrator] during the 15th century ce,

Young children gave
their lives to inca gods

In times of stress, called capacocha.

This ritual was often performed
on sacred mountain tops.

But in this case, there's something amiss.

[carla valentine] now a really
big telltale sign of human sacrifice

Is how the person died.

We know the inca used brutal methods.

Some common methods might be
strangulation or a blow to the head.

But this does present another mystery.

These children appear
undamaged and at peace.

The maiden is healthy, well nourished

And even her posture seems relaxed.

[bellinger] it looks as
if she's just nodded off.

It's pretty poignant actually.

[narrator] closer analysis of the
artifacts adds yet more intrigue.

The maiden's headrest feathers
hail from the amazon jungle.

While figurines are
made of spondylus shells,

That originate over 100
miles away on the coast.

We can see that these
are very high status objects.

These are associated with the inca elite.

One of the things you might ask is,

Are these children then
members of the elite themselves?

Are they royal children and that's why
they have such extravagant grave goods?

[narrator] to help untangle this mystery,

The mummies are taken to argentina's
institute of high mountain research.

With collaboration from the european
universities of bradford and copenhagen,

They're extensively tested.

So, what really jumps out
is the level of preservation.

Everything from fabric
and textiles to plant remains

To fingernails and hair.

The organs are undamaged
and there's even blood left

In the chambers of the heart.

[narrator] some content of
the digestive tract also remain

And can be analyzed.

Looking at the food content in
the stomach and the intestines

Gives us more clues
about the children's death.

[hassett] from the maiden's
stomach, we can see that

She probably had her last bit of
food between two to seven hours

Before she actually died.

And looking at her rectum, we can
see that she hadn't defecated after eating.

She wasn't in any great state of distress.

The artifacts placed
around her weren't disturbed.

So the evidence suggests
that the maiden actually did die,

In position, in her tomb.

[narrator] but still, the cause
of her death remains unclear.

Learning how the maiden
died on this bleak mountain top

Is key to solving this mystery.

[narrator] researchers hope a ct scan will
shed more light on the maiden's demise.

This is given to the digital forensics lab

For pathologist carla
valentine to scrutinize.

What I have here is a digital visualization

Of the maiden's ct scan.

It let's us thoroughly examine
the skeleton for any hidden trauma.

Let's zoom-in for a closer look.

There's no obvious fractures.
She seems pretty healthy.

But our digital model does
reveal something extraordinary.

Something you would not expect
to find in the mouth of a child.

It's this curious object clenched
between the maiden's teeth.

It's a bundle of coca leaves called a quid.

And users will get a narcotic
high from chewing this.

Effectively, it's just unprocessed cocaine

And has the exact same
effect as the powdered form.

Which suggests the maiden may
have been drugged in her final hours.

Why on earth would
anyone do this to a child?

[narrator] more disturbing,

This wasn't the only intoxicant
forced upon these young children.

We also find evidence of alcohol
consumption in all three children.

Likely a maize based
beverage called chicha.

The cocktail of coca and alcohol
probably made them pretty out of it.

[narrator] in argentina, three
amazingly preserved child mummies

Were found on a volcano summit.

Advanced tech has proved
the oldest, named the maiden,

Was drugged before death.

Investigators suspect it may
be linked to child sacrifice.

To dig deeper into this substance abuse,

They analyzed the maiden's hair.

Hair is like a chemical diary. Traces
of what we eat are locked inside.

Even 500 years later, we
can find out what they ingested.

And the longer the hair, the
further back in time we can look.

The maiden's hair is over eight inches long

And represents about two years of growth.

[narrator] chemical traces are
extracted from strands of her hair.

These are purified

And then identified using
a mass spectrometer.

The evidence from her hair shows
that about 12 months before she died,

She had a massive increase
in consumption of coca.

It's likely that this was
used as a sedative.

It was certainly not enough to kill her.

We also find evidence of alcohol
consumption in all three children.

Likely a maize based
beverage called chicha.

And we also find cups that probably
would've contained this chicha

Buried with the children.

[narrator] all the evidence points to a
rare form of incan ritualistic sacrifice.

One that shuns a horribly violent
death for something more merciful.

What would've been a potent cocktail of
drugs and alcohol in these kids' systems,

Probably meant they wouldn't
have had a clue what was going on.

One could look at this particular
ritual as a form of euthanasia.

These children would've
become important intermediaries

Between the worlds of
the living and the dead,

But equally they serve as a key reminder

Of the importance of paying
tribute to the inca emperor.

[narrator] the three child
mummies are now on display

At argentina's museum
of high altitude archeology.

All are a permanent reminder of capacocha.

These sacrifices had a hugely
important role in inca society.

It was part of how they maintained
their power and legitimacy.

[narrator] the altai
mountains, southern russia.

Archeologists excavating a remote siberian
cave make an extraordinary discovery.

Deep in the gloomy shadows of this cave, there
are tens of thousands stone age artifacts

Lying on the floor.

[mark horton] archeologists
find remains of bone

As well as worked jewelry artifacts.

These are items that have been
turned into obviously personal ornaments

Of one type or another.

[allan maca] the jewelry
includes ostrich eggshell beads.

Stone and bone pendants.

Among all these incredible objects there's
one that stands out above all others.

And it's a carved stone bracelet

Made from a very hard green stone.

[narrator] more eye-catching,

The bracelet contains a finely bored hole.

Compared to the other stone age items,

It appears at least 30,000
years more advanced.

The ability to polish this stone,

To carve this stone and
to also bore a hole in it...

This suggests a great
technological sophistication.

It doesn't make any sense.

Who was using these techniques
tens of thousands of years ago?

[narrator] for nearly a decade,
no one could answer that question.

Now, cutting edge analysis hopes to explain

Who made this sophisticated bracelet.

[maca] in a way, this
doesn't really make sense.

This really baffles the mind.

[narrator] the denisova
cave containing this discovery

Nestles in the altai foothills
near russia's southern border.

It's been a vital refuge, spanning
300,000 years of human history.

[horton] now this is
right in the center of asia.

And it's very dry and very cold up there.

So the cave deposits survive very well.

[narrator] to understand who
could've crafted the green bracelet,

Archeologists first need to
determine what era it came from.

Because it's made of stone,
we can't really carbon-date it

'cause there's no carbon in the stone.

So the only way we can date it is work
out a stratigraphic position in the cave

And date deposits that are
immediately adjacent to it.

[narrator] scientists test the sediment layer
the bracelet was retrieved from, using osl.

Optically stimulated luminescence.

Optical dating is a way of figuring
out when minerals in the earth

Were last exposed to sunlight
based on the energy stored inside.

[narrator] the result is beyond
anyone's wildest expectation.

We know from dating
the soil deposits around it,

That this bracelet is probably
40,000-50,000 years old.

This is remarkable.

Especially considering the advanced
techniques needed to make it.

[narrator] 50,000 years ago, early
humans possessed crude stone tools.

[maca] there're things
like scrapers, spear points.

Cutting tools in the stone
age or paleolithic period.

[narrator] it seems inconceivable

These could've created this
bracelet's precisely bored hole.

So experts check the dating
accuracy via another method.

Some other ornaments found in
the cave are made out bone and ivory,

Which can be radiocarbon dated.

[horton] radiocarbon dating these
personal ornaments had come out about

43,000-45,000 years ago.

So again, they seem to
confirm what the osl date is.

This bracelet is extremely ancient.

[narrator] this revelation deepens expert
resolve to track down the early humans

Who crafted this bracelet.

One species is immediately ruled out.

[koons] we know that homo
sapiens were in eurasia

Around the time the bracelet was made.

But the evidence is telling
us that it is not homo sapiens

Who were occupying the cave.

[narrator] instead, the spotlight
falls on the neanderthals,

Known to have dwelled in this region.

The neanderthals were a relative of
humans who lived in europe and asia

Until they became extinct
about 40,000 years ago.

We do know that neanderthals
made art and jewelry,

For example, in croatia, archeologists
have found modified eagle talons.

[narrator] so could this green bracelet
have been fashioned by neanderthals?

Some bone fragments found with
cave artifacts should provide the answer.

Scientists use advanced
genomics to trace their origins.

Scientists extract the dna from the bones,

Sequence it and compare it to databases

Containing sequences from
other early human species.

Some of the bones clearly
belonged to neanderthals.

But some of the bones
still can't be identified.

[narrator] these mystery bone samples
share commonalities with neanderthals.

Enough to raise a mind-boggling prospect.

There are some similarities between
the mystery dna and neanderthal dna.

It suggests we could be looking
at a completely new sister species.

[narrator] in russia, investigators
are trying to trace the early humans

Believed to have made a
sophisticated stone bracelet.

But dna analysis of bones found
in a cave with this precious item

Have only deepened the mystery.

[koons] we know that
neanderthals inhabited the cave.

However it looks like
another species lived here too.

[narrator] paleoanthropologists confirm

This is an entirely new human species.

It's named denisovan after the
denisova caves of this discovery.

We know about modern
humans coming out of africa.

And we know about neanderthals
that are living in europe.

But here in central asia was
a third species of early human.

It was one of the great
findings of the decade.

[narrator] branching off from a common
ancestor around 400,000 years ago,

Denisovans and neanderthals
co-exist on the human

Evolutionary timeline.

But the question remains...

Which of these two
species made the bracelet?

To find out, scientists use a
next level dating technique,

Called "relative genetic
aging" on the bone fragments.

We calculate relative genetic ages by
comparing the dna from these cave dwellers

To other human fossils and
counting the differences between them.

Mutations accumulate at a
known rate in modern humans.

So we can use that rate

To figure out how old
these ancient humans were

Based on the number of mutations
that have accumulated in their dna.

[narrator] applying a
complex statistical model

Finally provides an answer.

The youngest hominin fossil found in the
cave dates from 52,000-76,000 years ago.

Unfortunately, it's a real drawback.

This is thousands of years
before the bracelet was made.

[narrator] it's hugely frustrating.

Results show the
denisovans occupied the cave

Some 50,000 years longer than neanderthals.

But not enough to
crossover with the bracelet.

Experts believe they
remain the prime suspect.

[maca] recent analysis of
the finger bones of denisovans

Shows us that they apparently had
better manual dexterity than neanderthals.

Which may explain how they
might be the ones responsible

For fabricating the
beautiful stone bracelet.

[narrator] hopefully new evidence
will come to light proving this bracelet

Is indeed denisovan handiwork.

Heavens knows what new
discoveries will be made in the future.

At the moment we know
so little about them and their

Intellectual capabilities
and what they're able to do,

We really can't speculate.

I'm still rooting for the denisovans.

And I think many archeologists will be too.

[narrator] the state of yucatan, mexico.

Deep in the jungle,

In the ancient maya city of chichen itza

Lies one of the most
mysterious sights in the americas.

The temple of kukulkan.

This imposing temple is dedicated
to their plumed serpent god.

And it just sprouts
right out of the jungle.

It's a testament to the art and
architecture and the amazing building skills

Of the ancient maya.

However, even today there's surprisingly
little we know about much of this building.

[narrator] this 1,000 year old temple

Dedicated to the maya
god of the wind, sky and sun

Is one of the new seven
wonders of the world.

[sascha auerbach] along with
the great egyptian pyramids,

This temple is the most famous and
impressive pyramid of the ancient world.

But it's still a mystery to
us why it was built here.

[narrator] now, cutting edge
3d mapping will reveal clues

Hidden underground

That could finally unlock the
secret to kukulkan's location.

This new discovery
has the potential to rock

Mesoamerican archeology to its core.

[narrator] for centuries,

Kukulkan has fascinated the world.

The maya are renowned for
creating complex calendars,

Often integrated into their architecture.

Kukulkan is the most famous example.

[bellinger] kukulkan has 91 steps.

Plus one more at the temple on top.

If you multiply that by the four corners,

You come up with 365.

It's the number of days in a calendar year.

[narrator] an additional
phenomenon also connects

The temple to the passing seasons.

One of the most surprising and
spectacular pieces of evidence

Reveals during the equinox.

[narrator] during the March
and September equinoxes,

The god kukulkan appears
to manifest from out of thin air.

As the sun begins to set on these two days

A serpent appears to slither down
the northern staircase of the monument.

The maya would see this play of light
and shadow as the actual god kukulkan.

[narrator] this deity apparition leaves
little doubt to the temple's purpose.

But is there a reason for its location?

Investigators suspect the region's
remarkable geology offers a clue.

[thunder rumbling]

When it rains we expect
that water to run off

The surface and collect in rivers.

But that doesn't happen in yucatan.

The yucatan peninsula with
chichen itza and kukulkan belt

Has no rivers on its surface.

[narrator] the rocky landscape
is riddled with fissures

Funneling rainwater
into underground caverns

Known as cenotes.

Chichen itza means "at
the mouth of the well of itza".

The city is full of sinkholes
and cenotes which hold water

That can be then be used
for drinking or irrigation.

[narrator] but cenotes hold
an even deeper importance.

These cenotes

Were believed by the mayans to be portals

To the underworld that
was inhabited by the gods.

Among the most important
of them being chaac.

The god of life-giving rain.

[vranich] the maya believed that chaac

Held the waters of the
world in these large clay pots

And the sound of thunder were these
pots being broken open to release the rain.

[narrator] experts consider
whether these watery caverns

Now hold the key to this
centuries old kukulkan mystery.

[auerbach] cenotes are so absolutely
crucial to the mayan worldview

And to their understanding
of the cycle of life and death.

Kukulkan might have been arranged

Specifically based on the
placement of the cenotes.

Kukulkan could have a deeper,
darker purpose than we ever expected.

[narrator] in yucatan, mexico,

The stepped pyramid kukulkan

Is one of the great mysteries
of the mayan empire.

Experts believe there's a hidden
reason for its precise location.

But nearly 100 years of
archeological searching

Have drawn a blank.

This is one of the most
famous monuments on earth.

But it's still somewhat
of a shrouded mystery.

[narrator] in 2014,

The shallow geophysics group from the
national autonomous university of mexico,

Combined forces with the national
institute of anthropology and history.

They attempt a new survey

Using electrical resistivity tomography.

This is a method by which you
place a series of spikes in the ground

And pass electrical current through them.

And that current goes into the ground

And bounces off things
that are below the surface.

And as you do a series of these,

You can build up a 3d image of what

The buried substrata look like.

[narrator] the team had to develop
a special non-invasive method

To protect historic kukulkan.

Their efforts pay off.

It's a first survey of its kind,

To produce a detailed
3d image of the temple.

In the digital lab,

Historian sascha auerbach
is given privileged access.

Academics are really
excited about this survey.

It should open a new, hopefully
revolutionary perspective.

Let's add the tomography results.

Look at that. Look at how
that big blue space stands out.

Now in this survey, blue denotes
extremely low electrical resistance.

Far too low to be dirt or rock.

What we're looking at is a watery cavern,

Also known as a cenote.

This also looks like a pretty sizable one.

Using my digital measuring tool,

We can see that it's 114 feet at its widest

And it's over 65 feet deep.

Quite amazing.

Now we go back to our digital
map, we see something else.

As we pull out, two more cenote.

One to the north and one to the south.

But it doesn't stop there.

If we pull back a little bit farther,

We'll see that there are
two more of these cenote.

One to the east and one to the west.

Now let's connect them.

Look at that.

The great temple of
kukulkan sits at the epicenter

Of the maya spiritual universe.

This is truly remarkable.

The equivalent of the
sepulchre for christians

Or the kaaba for muslims.

The holiest of places
in the maya civilization.

[narrator] after centuries of mystery,

The discovery that kukulkan
was aligned with the cenotes,

Reveals this temple is not just a calendar.

It's a portal, through which they
communicated with the gods of the sky,

And underworld.

The temple of kukulkan
and the cenote beneath it,

Are the center of the axis mundi

Or the center of the
world for the ancient maya.

The place where the maya
ceiba tree of life was planted.

The branches of the
ceiba reach up into the sky.

They represent the upperworld.

The body of the ceiba is this
world where the humans live

And the roots of the ceiba
extend down into the underworld.

And so the ceiba tree links
together the three worlds

Of maya cosmology.

[narrator] umbria, central Italy.

Archeologists from
the university of arizona

Are excavating the necropoli dei bambini,

Otherwise known as the children's cemetery.

It dates to the fifth century ad,

And in the ruins of this villa

Were a number of child burials,

Including fetuses and young children.

[narrator] among piles of bones,

The team makes a heart-stopping discovery.

[kiki sanford] there's
a skeleton of a child,

Lying on its side, and a brick
has been forced between its jaws.

I have never seen a child buried like this.

This is a really unusual burial phenomenon,

In an extremely emotive context.

[narrator] some suspect this
is a portent of the evil undead.

According to classical texts, the
unusual burial practices such as this,

Were reserved for individuals who
they believed were the unquiet dead.

It counsels the living to place a
stone in a child's mouth to prevent them

From causing harm to others,
after they become a revenant.

Someone who comes back to life.

The idea being

The soul of the dead individual
passes out through the mouth

And haunts the world.

[narrator] now, revolutionary
science investigates why this child

Suffered such harsh treatment in death.

We have to understand that
the mid-fifth century here in Italy

Is a time of upheaval.

But, what could possibly explain
such a disturbing burial of a child?

[narrator] in 2018, archeologists
excavating an italian children cemetery

Uncover a sinister makeshift tomb.

Inside, a small corpse has
a stone wedged in its mouth.

The burial site is creepy as hell.

[narrator] rubble is
scattered across the skeleton.

So initially they consider if the
stone accidentally fell into the mouth.

Natural jaw opening, as
the muscles decompose,

Is actually quite common and it's
found often in bodies that are in coffins.

But it's much less likely in bodies

When they're lying on their side.

It looks like the jaw has
been intentionally forced open.

[narrator] further analysis of the
stone confirms this was a deliberate act.

The stone in the child's mouth
has a real crystalline sheen to it.

It's obviously not the same as
the stone used for masonry nearby.

This is not a random occurrence.

[horton] also seems to have
some evidence of shaping,

Possibly in order to fit
inside the person's mouth.

[narrator] having established foul play,

Forensic anthropology
helps build a victim profile.

Initial examination of the skeleton
can't tell us if it's a male or female.

But, based on the dental
eruption of the teeth,

We can tell that this child was about
eight to ten years old when it died.

[narrator] but curiously, investigators
can find no skeletal evidence

Why this young child was so badly treated.

They widened their
search for material clues.

So, in this cemetery, there
are a number of other finds that

We might consider really quite creepy.

There are raven talons,
toad bones, cauldrons,

Bits of ash and signs of burning,
and even sacrificed puppies.

[horton] what's interesting is with this
array of what appear to be cult-ish objects.

That maybe, you know, some idea of magic

Or something supernatural,
maybe being going on here.

[narrator] it bears the
hallmarks of paganism.

In fifth century Italy,
christianity has taken root.

Anyone displaying idolatrous
beliefs is savagely persecuted.

The stone in the mouth may have
been a supernatural safeguard.

The mid fifth century
is a significant time.

We are right at the cusp
of the medieval period.

Many of the smaller towns and villages

Still retain their folkloric
and superstitious practices.

There was a deep fear of the undead.

The notion that people wouldn't
properly die and go to the underworld,

But their souls, their spirits would
stay in a state of suspended animation

To haunt the present.

So if you can insert a stone in the mouth,

Would let you block the spirit
inside the body when you bury it.

Then you can avoid the
whole issue of undead.

[narrator] but any thoughts this
child was possessed are banished

When scientists analyze the
cemetery's charred deposits.

Sprinkled around the burial site,

There are several patches of what look like

Small grains of charcoal. But
under a microscope, we can tell,

This is the remains of honeysuckle.

It must've been important. They
were sprinkling it all over the place.

[narrator] records reveal,
this sweet smelling flower

Was once regarded as an important panacea.

[horton] in the ancient world,
honeysuckle was not only a cleanser,

But was also seen as a
medicine to salve diseases,

Internal diseases particularly for spleen.

[narrator] armed with this knowledge,

Scientists re-examined the child's
skeletal remains for evidence of disease.

The child lost a tooth before they died.

It appears to be the result
of a periodontal abscess,

Which is a pocket of pus
in the tissues of the gum.

Several diseases are linked to children
getting periodontal abscesses like this.

Chicken pox, measles and malaria.

Most importantly we know it's a
disease that causes an enlarged spleen.

[narrator] to check for malaria, a
ground-breaking test is used on bone samples

Taken from the cemetery.

The malaria parasite excretes hemozoin,

Which you can actually find by
using x-ray diffraction techniques.

Going into the bones and
cells to identify this molecule.

When you look at the results, you
see these big, black, crystalline lumps.

And that is a very clear
sign that this is malaria.

[narrator] malaria in cemetery samples,
together with historical accounts of

Regional pestilence suggests a
huge local outbreak of the disease.

And helps explain why a stone
is jammed in the child's mouth.

The physical symptoms of
malaria can be quite terrible.

I mean, imagine watching a child go into
an open-eyed coma and start convulsing.

You can completely understand why
ancient people would have prescribed this

To malignant supernatural forces.

Placing the stone in the
child's mouth was both a literal

And symbolic way of incapacitating
the child and keeping them

From coming back to plague the living.

[narrator] southern
scotland, united kingdom.

An ancient iron age hillfort flanked
by two unusual roman camps,

Has flummoxed experts.

On the north, the imprint of the roman
encampment doesn't follow the standard,

Symmetrical rectangular
plan. It's strangely elongated.

And to the south, this encampment is wonky,

And has three wide
gateways, facing the hill.

[narrator] adding
intrigue, during the 1960s,

Archeologists discover
a huge pile of slingshot

Strangely accumulated
at the hillfort entrance.

These are small pieces
of lead used as projectiles

By roman infantry men who had slings.

We know the romans
were obsessed with training.

And the fact that these slingshots

Were concentrated towards the gate suggesting
that maybe they're out there practicing.

A sort of target range if you like.

[narrator] for three centuries this ancient
hillfort has been a source of controversy.

Some scholars suggest that this
is the site of a roman training camp,

And others actually have studied it

And say, "no this is the
place, the site of a brutal siege."

[narrator] now it's hoped a
unique archeological discovery

Will finally settle this mystery
and reveal what actually took place

At burnswark, 1,900 years ago.

It's a mystery that has permeated
decades of research and still

People are trying to resolve
what really happened here.

[narrator] in burnswark,
scotland, an iron age hillfort,

Pincered by two oddly configured
roman camps has divided archeologists.

- Some believe it's a training site.
- [soldiers shouting]

[narrator] others, a battlefield.

It's a mystery that has
baffled scholars for ages.

[narrator] in 2015, investigators
revisit this former stronghold

- Of the caledonian selgovae tribe.
- [tribesmen shouting]

[narrator] they attempt to
crack this half century riddle

With battlefield archeology
and modern technology.

Battlefield archeology was
developed to better understand

Kind of, civil war sites

And battlefields by using
sensitive metal detecting

To look at the distribution of
musket balls across the site.

But it works in the same manner
to survey roman battlefields

For sling bullets and arrowheads.

[narrator] a survey of the 17 acre site
reveals far more than anyone bargained for.

Literally thousands of metal objects
scattered across the landscape.

[narrator] a third of the
finds are roman sling bullets,

Most of the standard lemon or acorn shape.

But there's also a new
radically different type.

These are very unusual objects.

They were smaller than
your standard sling bullets.

These artefacts are about an inch
long and they weigh less than an ounce.

What's really interesting about
them is that they have a small hole

Bored into one side.

It's very clear that these are specifically
engineered, but for what and why

Has been baffling.

These perforated bullets may be the key

To finding out what really
happened here at the hillfort.

[narrator] the only way to determine
their true purpose is to test them.

- As they take flight, all hell breaks loose.
- [whistling]

What they discovered is that these objects
created this high pitched whistling,

And they have what's
called an aerophonic quality.

Hundreds of these sling bullets raining
down made a cacophony of sound.

-[whistling] -it would scare
the daylights out of anyone.

[dills] they were
nearly invisible in flight.

So you didn't know when and
where they were going to hit.

They would have been used
to create terror and chaos.

[narrator] this astonishing
revelation undermines the theory

That burnswark was a roman training camp.

The modified holes represent an additional
step in the manufacturing process.

This is additional labor.
It would be unusual to use

Valuable ammunition
like this, just for practice.

It now seems likely that a merciless siege

Or at least a major
skirmish occurred right here.

[narrator] but conclusive proof is needed.

That requires somehow dating
these whistling shots to the roman era.

[horton] we can't directly date these
slingshots because they're made of lead,

They're not made of carbon. So
you can't use radiocarbon dating.

But what we can do is
compare them to other sites

Where slingshots have been found.

Sites that are directly
dated to this period.

[narrator] isotope analysis is used
to chemically fingerprint the slingshot.

This is cross-checked against
catalogued roman shot to get a match.

The bullets from the burnswark site
have the same signature as bullets found

At a nearby roman site called birrens.

Now, in birrens, these bullets

Were excavated in a context
that allowed us to date them

From the antonine period.

This is the reign of the
emperor antoninus pius.

[narrator] antoninus pius is regarded
as the emperor of peace and prosperity.

His reign characterized by
vast construction projects.

In 142 ce, he orders the
building of the antonine wall,

To keep raiding caledonian tribes at bay.

[horton] the romans had a
problem in defending their frontiers.

A decision was made to extend the roman
empire northwards from hadrian's wall,

To the link between the
plate and the four estuaries

And to build a new wall between
the two to annex southern scotland

Into the roman empire.

This puts the roman army on a collision
course with the burnswark hillfort.

[narrator] burnswark is occupied by
the selgovae tribe, meaning the hunters.

These fearsome warriors demanded
rome's most formidable terror weapon.

Thousands of these slingshots
whistling through the air.

This must have been quite terrifying.

These sling bullets are an incredible
find and show us how important it was

For the romans to take this hillfort.

They were willing to employ their most
innovative weapons to expand their empire.