Original subtitles

NARRATOR: The apocalypse...

..when an entire people...

..are destroyed.

Or destroy themselves.

The end of civilisation.

For us today, as we go about our daily lives,

it's barely something we consider.

We're so sure it couldn't happen to us.

But for some civilisations...

..it already has.

Since the dawn of human history...

..we have told each other stories about the sea.

About its power over life...

..and death.

In the 'Torah',

the 'Qur'an',

and the 'Bible'

is the story of the great flood.

When Noah built an ark,

as the sea flooded the land, killing everything in it's path.

Societies all across the world are replete with examples of stories

of lands that have been lost and covered over.

People have done something wrong, and this is God's punishment.

Or the story of the lost city of Atlantis

told by the great Greek philosopher, Plato.

The utopian island that people have devoted their lives to finding

beneath the waves.

Right across the world in almost every culture

there is a flood story.

A story where water can both cleanse and destroy.

Across our planet are myths and legends

of the sea rising up and wiping out civilisations.

But what if these stories aren't just stories?

Scientists now claim to found a lost world

at the bottom of the sea...

..called Doggerland.

It existed about 10,000 years ago,

and was a place that was almost perfect

for its stone age inhabitants.

It's a rich place, it has wetlands.

Where you had wild fowl in abundance,

where fish in the rivers were migrating,

where you had all the animals and plants that you'd want,

and also all the resources.

Flints, and wood, and everything else was out there.

Doggerland's temperate climate

would have made this a beautiful and abundant region

for its hunter-gatherer population.

Plants and animals that we recognise today.

Hazel, ash, pine, large game.

Horse, bison, deer, antelope and elk.

Doggerland sounds like paradise.

But this world no longer exists, so we must as the question,

what exactly happened to Doggerland?

Our search begins in the north sea.

This sea was created at the end of the ice age,

about 15,000 years ago.

As the ice melted and receded,

it created the North Sea between Scandinavia,

northern Europe, and the UK.

Its power and hidden depths have captured the human imagination...

..and it has also, for thousands of years,

provided humans with a staple food.

Fish.

From the east coast of Great Britain,

the British have for generations sailed from the ports of Norfolk,

100 miles north east of London, to fish the North Sea.

And in September 1931,

a vessel was trawling...

..near the Leeman & Ower Banks.

It was captained by pilgrim, E Lockwood.

About 25 miles out he lowers his nets,

and he trawls the ocean for fish.

As he lifted them up into the boat,

among the sort of shining fish

is a massive what they call peat log.

It's a big like, boulder,

not of rock, but of mud.

He and his men start breaking it up with shovels.

As he puts his shovel in it goes dink,

and he's like, "That's really weird, that sounds a bit like metal."

So he digs through it, he uncovers a sort of black shape,

and on it is a load of ridges cut into it,

so it's sort of almost like a barb,

and it's got little grooves at this end.

So presumably this is some sort of like, you know, harpoon,

or hook or something.

He prised away and found a lovely bone antler harpoon point.

Intrigued, you don't find these everyday in the North Sea,

he brought it home.

Lockwood had found an implement

made out of the bone from a deer's antler.

About 15cm in length,

and with a serrated side

so it could be used to harpoon prey.

But how on earth did it get there?

Because it's in a load of mud which has been under the ocean.

What was the harpoon doing in the middle of the North Sea?

Who made it and when?

Our story now moves to Cambridge University.

Here, in 1932, works a young, ambitious archaeologist

called Grahame Clark.

Clark would go on to become one of Europe's

greatest archaeologists,

seen here winning the Erasmus prize in 1990.

Grahame Clark who's a very tenacious scholar,

he wants to make a name for himself

and he's decided to study a whole new area

that hasn't really been looked in to before,

which is the Mesolithic, the middle stone age.

Clark was fascinated by the period

from about 10,000 to 4,000 years from today.

Clark believed the harpoon from Lockwood

was similar to those used by Mesolithic hunter-gatherers

in Scandinavia known as the Maglemose.

But this creates a greater mystery.

Mesolithic hunter-gatherers were known to be able to fish,

and had fishing boats.

But what were they doing harpooning fish so far out to sea?

The first step for Clark

was to identify that the harpoon was indeed Mesolithic.

Today, scientists rely on a process called radiocarbon dating.

This involves measuring the decay of the isotope carbon-14...

..and comparing that to levels of carbon dioxide in the atmosphere.

But without this complex, modern technique...

..how would Clark date the harpoon?

To try and solve this,

Clark turned to his friends and botanists,

Harry and Margaret Godwin.

The Godwins were a husband and wife couple,

and they were from the University of Cambridge,

same time as Grahame Clark, and they specialised in palynology,

the study of plants and their remains,

things like pollen.

Harry and Margaret Godwin were working on a technique

that relied not on the decay of carbon isotopes to date objects,

but instead used ancient pollen.

The Godwins might not be able to date the harpoon itself...

..but they could date the peat it was found in

through pollen analysis.

They specifically went out

and trawled up another block of peat,

very, very close to where they'd found the harpoon,

and actually analysed it.

What the Godwins found

would change the way the seabed of the North Sea is seen forever.

It was showing things that we have today.

Pine trees, alder, as well as things like oak.

You know, this wasn't a block of mushy mess

that had come from an estuary,

this was a part of a landscape that was living and breathing

with all the things that we would expect on dry land today.

These were plants which were nowhere near the sea,

so what on earth are they doing underneath the North Sea?

What the Godwins now had to do was work out what time period

these types of tree and pollen were from.

Working with other scientists in Scandinavia and Germany,

they had built up a list of timezones, or chronozones...

..based on pollen found in prehistoric peat.

The results are as Clark predicted.

The pollen in the peat near where the harpoon was found

dates to the Mesolithic age.

This proves the harpoon is most likely from that period.

But what Clark still can't answer

is how did the harpoon get to the middle of the North Sea?

Could the peat, pollen and harpoon

really have been washed out that far into the North Sea?

Clark created a map showing pollen discoveries across northern Europe.

And he wondered if there wasn't a landmass...

..now hidden under the North Sea...

..that had once linked all of northern Europe.

A land that could have been inhabited...

..by Mesolithic hunter-gatherers.

As it turned out...

..Clark wasn't the first to come up with this unusual idea.

In the early years of the 20th century...

..the botanist Clement Reid,

used to walk the beaches and sand dunes of Norfolk,

in England.

As a botanist, he was fascinated by the plants and trees of today,

and where they had originally come from.

Clement Reid became obsessed with a thing called Noah's Woods.

What it is, is when the tide goes out in some locations,

you can see tree stumps, which is a bit odd.

Loads of people at the time called this phenomena Noah's Woods,

'cause they thought they were leftovers,

remnants of Noah's flood.

But Clement Reid didn't think that was possible,

so Clement Reid got the bit between his teeth

and decided to investigate.

Reid dug beneath the coastlines, and into the depths of the sea,

to see what he could find.

He asked the question, "Were there forests and animals

"living in these areas thousands of years ago?"

From his finds, Reid came up with a theory

he published in a book called 'Submerged Forests'.

It suggested that somewhere under the North Sea was a landmass.

A landmass that could support forests and animals.

Reid suggested there was an alluvial plane

connecting all of northern Europe,

with its heart at somewhere called Dogger Bank.

Clement Reid writes this amazing book

called 'Submerged Forest',

where he theorises a massive landmass

linking the UK to the rest of Europe.

He had so little evidence for it though,

nevertheless, this was a book that was really groundbreaking.

His main issue was that nobody really cared,

nobody was really obsessed with this subject as much as he was.

Reid's was a pretty unusual idea,

without much evidence to support it at the time

and his work was derided by the scientific community.

Reid's work was seen as nothing more than science fiction,

and was all but forgotten until 80 years later.

In the 1990s, pioneering British archaeologist,

professor Bryony Coles became intrigued about Reid's work.

At the time of Professor Coles' work,

oil exploration in the North Sea was developing rapidly,

allowing unexpected avenues of research.

There was the geological surveys

coming from things like the North Sea oil explorations

of that period.

I began to draw together the geological

and the archaeological evidence

that this was a terrain that had its contours, its river systems,

that these were things that we were totally unaware of.

Professor Coles used numerous maps,

including the ones made by Grahame Clark in the 1930s,

to estimate how the ice caps melted after the ice age,

and what land masses that might have created.

I realised quite soon that we needed to have maps

showing the changes at intervals,

because things were changing

and it might take thousands of years to change.

Coles work suggested that in the region where the harpoon was found

there might actually have been dry land.

But would anyone accept Professor Coles' idea?

When I was doing the mapping

I realised that it would be much easier not to have to say

the land that used to be under the North Sea every time,

but to give it a name of its own.

To get across the idea that it had been not just a drowned landscape,

but a living, live, dry land landscape.

Based on the name of the fishing area, Dogger Bank,

Coles called this new land mass Doggerland.

And that's really important,

because as soon as somewhere has a name,

it becomes a place

not just in reality,

but also in the imagination.

And Coles went on.

She posited the theory that not only was Reid correct

about the existence of a lost land mass in the North Sea,

but it meant something even more unexpected.

It was a huge area with rivers, with bays and inlets,

with areas of high ground, hills if you will,

and low lying areas that are now entirely submerged,

but then would have been absolutely

at the heart of the post-glacial landscape of northern Europe.

So if this was a landscape,

was there evidence to suggest that it had one day supported human life?

Across the North Sea, in present day Holland,

a few hundred miles for Norfolk, is the beach of Zandmotor.

There, beach combers hunt for hidden treasure.

Coins, bones, a message in a bottle...

..anything unusual gifted by the sea.

(SPEAKING IN FOREIGN LANGUAGE)

The beach combers coordinate their finds with Dr Luc Amkreutz...

..a specialist archaeologist from the nearby University of Leiden.

They work with Dr Amkreutz

because Zandmotor beach isn't like any other beach.

I'm sitting here on Zandmotor beach, but it's not an ordinary beach,

it's a beach created by man in 2011,

by spraying a whole lot of sand from the North Sea

on this beach plane.

It as constructed out of materials dredged up from the sea floor,

11km off shore, and dumped on the existing beach.

Material dredged from an area of the sea

close to where Lockwood found the harpoon.

What was so special when they created this beach,

is that all kinds of objects came to the surface.

Wow.

They would eat bones of animals living in,

for instance, the ice ages.

Like woolly mammoth and woolly rhinoceros.

Most astonishing of all is that it wasn't just the animal remains,

but amongst these there were also

hundreds of artefacts made by humans,

and even by neanderthals, which is of course really strange,

given that they come from the North Sea.

Over the years,

beach combers have found more than 500 ancient artefacts,

including tools, bone fish hooks...

..and even human remains that they say are thousands of years old.

Zandmotor, and certain other areas,

really brought home the enormity of this huge archaeological archive

in front of our coast.

We have this whole range of organic artefacts that is preserved,

and is actually basically as if you're looking at a complete

carpenter's tool set.

And it really brought home the idea of this is a whole world,

a whole people landscape that was there, which is now lost.

The more touching finds from Doggerland

are not just the artefacts, but the human remains themselves.

And one story I find particularly moving, is this lower mandible,

this person was about 40 years when he or she died.

You're not just looking at the objects,

or you're not just looking at the foot remains,

but you're looking at the actual people themselves.

And Luc's group are not the only ones finding things on the beach.

Since the 1970s, hundreds of amateur archaeologists

have made findings on the coasts of the Netherlands, Germany,

Denmark, Sweden, Norway, and the UK.

Under the North Sea there are signs of an entire living world...

..of not just animals, but also people.

But the question remains...

..who were they and what happened to them?

In 2005, a European team of scientists

centred at the University of Bradford in the UK...

..wanted to see exactly what Doggerland might have looked like.

But they knew it wasn't going to be easy.

The area obviously was very inaccessible.

It's obviously underwater between,

you know, five and 30m in some places,

down to 60, 80 in others.

Obviously that water is very cold, so you can't go diving easily in it.

It's very powerful currents in some places.

The other thing, of course,

was the technologies, and the techniques that were used

hadn't been developed in some cases, or were in their early infancy.

There was no way that archaeologists could excavate under the sea bed

in these dangerous waters.

It was beyond their technical abilities

and would have cost hundreds of millions of Euros.

It looked like Doggerland

would remain forever a subject of speculation and mystery,

unproven by scientific fact.

But at a yearly symposium, one of the PhD students at the time,

Simon Fitch, had an unusual idea.

As I was sitting there in the lecture hall,

I realised that actually I'd worked on material,

you know, seismic data which came from that area,

and that data possibly could be re-tasked,

it could actually be used to look under the water,

to see the landscape.

In the early 2000s,

the North Sea was going through a renewed oil and gas boom.

Billions of Euros' worth of oil and gas were being discovered

using new technology.

If the Bradford team could access the data from that technology,

then maybe they could see under the seabed,

and whether there was evidence that Doggerland did once exist.

The Bradford team approached oil and gas exploration companies

to access their specialist mapping data.

Surveyors for oil and gas exploration were going up and down,

surveying the North Sea with a fine-toothed comb,

to pull together a series of contour maps of the sea floor.

This was a huge swathe of land,

tens of thousands of square kilometres.

What the Bradford team wanted in particular

was the data for 3D seismic maps.

These are created by specialist ships

dragging thousands of listening devices

called hydrophones along the surface of the sea.

They listen to sound waves

bouncing off whatever lies beneath the seabed.

The resulting data shows where, hidden under the seabed,

there may be deposits of oil or gas to drill for.

Seismic mapping is a really good way to do a quick analysis

of a large amount of submerged landscape.

Mapping the sea bed in the same way as we see inside a stomach

when we're doing sonograms, for instance,

and you use the sonar pulses, and you get a little echo back,

and you get the shape appearing on the screen.

But would this help the Bradford team?

Could the data help build a picture of a land

now hidden under the sea bed?

Having waited some months

the team finally got the data for the Doggerland area.

They inputted it into a computer...

..they waited for the first seismic maps.

So we plugged that in, and then put it into the computer,

and up popped this remarkable image.

We could actually see a river which was alive and vibrant

when the Mesolithic people were wandering round

on top of Dogger Bank.

It was a phenomenal almost like lunar landing type of moment.

You know, you felt you were seeing something

which no one had ever seen before.

I think that was when all the jaws dropped,

and we realised the implications of what we were looking at,

and was providing a doorway into a lost world,

it was just a phenomenal realisation

that all those questions the people had had before us

could be answered.

It was just as Bryony Coles and Clement Reid had suggested.

A hidden world of rivers, lagoons, and wetlands.

We could map features in the landscape.

We've seen rivers, we've seen lakes, we've seen little hills,

we've seen everything in a landscape you'd expect in a normal country,

except this is under the sea and it's preserved,

and it's caches of material and archaeology sitting out there

waiting for us to go and find it.

The Bradford team had seen Doggerland for the first time...

..but the mapping still didn't answer the biggest question.

What happened to the peoples who lived there?

To understand that scientists had to investigate

how the people might have lived.

Human evolution is heavily influenced

by geography and climate.

So the first thing to establish

is roughly what kind of climate Doggerland would have had.

This is done by looking at the position of Doggerland

geographically at the time.

We know that immediately after the end of the last ice age

it was frozen, it was like the Siberian tundra,

but then very rapidly started to warm, to thaw out,

and that enabled new species to start to colonise this land.

Doggerland would have grown into a landscape

that we would recognise now.

The winters were shorter and less harsh,

and the summers were longer and warmer.

And plants start to colonise this land, trees start to grow.

A lot of the species that we're familiar with now,

so hazel, ash, oak, willow.

Animals start to colonise, because they're following the food.

So you get herds of horse, and bison, and elk.

But the question remained,

could Doggerland support human populations?

And if so, what would those people have been like?

A clue comes from Yorkshire in northern England.

In 1948, Grahame Clark,

the archaeologist who had dated the harpoon

from the North Sea,

was told of a discovery of flint and bone

at a place called Star Carr.

10,000 years ago it was on the edge of a massive paleolake.

Because of the nature of this landscape,

and the waterlogging in the modern farm land,

it means that there's been an incredible level of preservation

at Star Carr.

For the next three years, Clark led the dig at Star Carr,

and his team uncovered one of the best

Mesolithic settlements in Europe.

So we have organic remains, animal bones.

There are harpoon points

beautifully crafted from deer antlers.

By looking at Star Carr today we can build a picture

of what lives the people of Doggerland might have led.

The site has been further excavated by Professor Nicky Milner.

I think it's very easy to sometimes look at the past

and think back 11,000 years,

and that people must have lived very basic lives.

But the evidence that we've got from Star Carr

is that they were very good at making things,

at crafting things.

Star Carr shows many tools made from animals,

and made to kill animals,

similar to the harpoon Lockwood found in 1931.

We have all sorts of animal remains, and plant remains from the site,

which shows us the types of animals they're hunting,

and their expertise in gathering and living off the land.

They're hunter-gatherers, and these are bushcraft experts,

they're armed with a whole range of skills and expertise

that means that they can thrive in this landscape.

At Star Carr is also what's known as the oldest house in Britain,

dating from about 9,000 years ago.

So we found a number of houses

which are the earliest known houses in this country,

so that told us that people

were able to build structures out of wood.

We understand more about their woodworking skills,

and how sophisticated those must have been,

and that they could make structures, and that involves team work.

Mesolithic people, it appears, were hunter-gatherers,

they were highly mobile,

but they were also living together and growing together as a community.

If we're now thinking about people

who have places that they regularly spend long periods of time at,

that they invest their resources in to build houses,

no longer could we write these people off as simple,

knuckle-dragging, cave dwellers clad in simple animal skins,

eking away a living at the edges of the ice age.

These were people who shaped their landscape.

One of the most unusual finds at Star Carr

was shaped from the skulls of killed deer.

One of the most iconic and remarkable discoveries

from Star Carr are the antler headdresses,

and they've been shaped by human hands over hours,

and hours, and hours of labour.

The head dresses are really mysterious.

There are none others known in this country,

and only a few in the rest of Europe.

They're made of red deer skulls with the antler coming out of them.

There are two main theories,

one is that they might have been used as disguises

in hunting practices,

and the other is that they might have been used by shamans

in some kind of ritual practices.

The headdresses offer clear incontrovertible evidence

that these people had a sophisticated culture

to create these artefacts that have no functional purpose,

but clearly have a very important spiritual purpose.

Star Carr helps build a picture

of how sophisticated people might have lived on Doggerland.

But who were these people?

What did they look like?

To see what a Mesolithic person might have looked like

we must travel to the south of England...

..and the Cheddar Gorge.

It was here that one of Europe's oldest Mesolithic men,

Cheddar Man, was found.

Cheddar Man is one of the really important discoveries

in this country.

Cheddar Man was found over 100 years ago in Somerset,

and has been studied a lot ever since

because human remains are incredibly rare,

particularly in this country for the Mesolithic.

Cheddar Man is the oldest British,

most complete human skeleton that we have.

It dates to around 10,000 years old.

And in 2018,

a groundbreaking analysis was made of Cheddar Man's DNA

in an attempt for us to meet our ancestors face to face.

It gives us an insight into what people looked like,

and what we know from Cheddar Man is he was about five-foot-five,

from the DNA we know he had dark, curly hair, blue eyes,

and darker skin than we imagined,

certainly darker than European skin tends to be today.

So although he looks quite striking to us,

he would have looked quite normal then.

Now we could finally see the faces of the sort of people

that would have lived at Star Carr and Doggerland.

Despite living thousands of years ago,

it helps us understand who lived here...

..but it still doesn't answer the big question,

how did people who made Doggerland their home come to disappear?

To understand better what might have happened,

the Bradford team decided to actually dig into Doggerland.

They did this by taking core samples.

If you take a giant pipe, you ram it into the seabed,

and then you pull it out,

the column of mud that you pull out, that's a core.

So when you look at a core,

what you're effectively looking at are slices of time,

it's like a diary of the deep past.

They are hugely important for our understanding

of how our climate has changed,

and environmental conditions have changed,

and they're also crucial to our understanding of the archaeology

of Doggerland and what happened to the people.

What the Bradford team saw is how.

With the end of the Ice Age

the sea level was rising at over a metre every 100 years.

Those sediments preserve in them a record of how sea level changes.

So at one particular site

it will show the history of going from dry land

through to the era becoming waterlogged,

and eventually being submerged.

But the team noticed that in one particular time period

the sea levels seemed to rise significantly.

If you look at the cores taken from Doggerland,

when you get to 8,000 years ago there's a huge change.

But what caused this huge change?

And what effect did it have on Doggerland?

Around 8,000 years ago there is what is called the 8.2-kilo year event,

meaning 8,200 years from today,

or roughly 6,250 BCE...

..scientists noticed that the planet's sea levels

rose dramatically.

One explanation for this change is with the warming of the planet

after the ice age...

..came the collapse of a colossal ice sheet into the Atlantic Ocean.

The Laurentide Ice Sheet,

in what is present day North America.

At its peak, the Laurentide Ice Sheet covered most of Canada,

and a fair proportion of the top of the United States.

Ice was over what is now New York, and Chicago, and St Louie.

This was millions, and millions, and millions of tons of water,

locked up in ice.

This was the biggest release of fresh water

into the North Atlantic for 100,000 years.

So profound was this change that it dropped the sea temperatures

by a degree almost overnight, and that changed the gulf stream,

which changed the air temperatures

by up to 1.5 degrees centigrade in a generation.

As the melt water filled the oceans,

global sea levels rose by as much as half a meter in a few months,

threatening lowlands like Doggerland.

All the reasons that made Doggerland

a fantastic place to live as a hunter-gatherer

also made it particularly vulnerable to sea level change.

It was low lying, it was cut through with rivers, and streams,

and marshy areas, which was fantastic for fishing,

and fowling, and gathering those wild resources,

but it also meant that if the sea levels rose,

it would be inundated, and inundated very rapidly.

The sea level rise was so pronounced

that it turned Doggerland into islands.

Doggerland would now have been cut off

from continental Europe and the UK.

So what did this mean for the people on Doggerland?

After the 8.2 event the sea levels rose so significantly

that it was easily within generations,

easily within peoples' lifetimes.

They could easily see the effects of sea level rise.

These people had an intimate knowledge

of the landscape around them,

and for that to start changing

must have been extraordinarily disorientating and confusing.

What would have been fertile river valleys

suddenly became flood valleys.

Huge swathes of low lying land

would have been lost almost immediately,

and that destroys the animals you're relying on,

that destroys the plants you're relying on.

And so when all this changes,

this puts huge pressure on the people living there,

and it would have been scary for them.

The hunter-gatherer paradise of Doggerland

was slowly sinking beneath the waves.

So what could Mesolithic people do?

If you're a Mesolithic person

and your land gets flooded where do you go?

Well you obviously, you know, follow the animals,

follow the herds, that's you know, where you food source goes,

so you're going to do that.

'Cause some of them would have gone to Britain,

and what is now mainland Europe.

Some of the people would have relocated

into other parts of today's Europe,

like Germany and Netherlands, and others to Great Britain.

From the archaeological evidence

we have a number of Mesolithic boats.

It's exactly at this point, as the sea levels are rising,

that we start to get this really good evidence

for the use of dug out canoes in Britain and northwest Europe.

Hunter-gatherers are fantastic at being flexible,

and maybe even people started adapting

to being much more sea dwelling.

But the question remained...

..what happened to the people who stayed on Doggerland?

As the Bradford team looked further into the core samples

they found something that would have been terrifying.

They found what might be the key to the apocalypse of Doggerland.

In a time period around 6000 BCE

the core samples looked more mixed up than expected.

It was a series of sand, shell,

jumbled up with sequences within which looked so unusual,

so different to everything else we'd seen in our careers,

except for the few samples we've seen published in literature,

which were tsunami samples.

This mixing up of sediment suggested huge force.

A great wave of power...

..a tsunami.

But what could have caused such a wave?

The team connects the unusual core samples

to an event called the Storegga Slide,

when vast areas of the Norwegian continental shelf slid into the sea.

The Storegga Slide was a huge submarine landslide

that occurred off the coast of Norway.

The slide itself is made up of sediments

deposited from the glacial era,

so it's a lot of fine muds and sands,

and within it there are lots of weak layers,

this are layers that can't really hold all that sediment together,

so they're very prone to slipping.

So any trigger, like an earthquake,

is enough to set this sediment in motion and move down the slope.

And as it does so, it will generate a wave,

'cause it will disturb the surface of the water.

A tsunami would have been terrifying,

and is something that our modern society has witnessed

in both 2011 in Japan...

..and across Asia in 2004.

You can see here how the 2004 tsunami spread across

almost the entire globe.

So what effect would the Storegga Slide tsunami

have had on Doggerland?

Dr Jon Hill of the University of York

recreated how the tsunami might have hit northern Europe

in a series of computer simulations.

The Storegga Slide involved 3,000 cubic kilometres of sediment,

and it probably moved in one go very quickly.

So this huge slide,

which is probably one of the biggest landslides

in the history of the Earth,

generated a huge tsunami

which then travelled across the North Atlantic to Greenland,

and then down the North Sea with a tsunami of ten to six metres

impacting the coast of the UK.

In this scientifically accurate simulation,

the remaining islands of Doggerland

are repeatedly washed over by the elevated red waves.

The core samples also suggested that the timing of the wave

was critical for people on Doggerland.

So one of the things I find surprising

is our ability to pinpoint the time of year that Storegga occurred.

So we do this by looking at the sediments

that have been deposited,

and in them we find bits of vegetation

like mosses and cherry stones,

where we know that they would have occurred in the autumn,

and hence we can find out

that the Storegga Slide actually happened in the autumn.

It is believed that Mesolithic people in the summer

went inland to hunt deer,

but in the autumn, with fewer deer to eat,

they returned to the shoreline.

The tsunami from the Storegga Slide would have hit the Mesolithic people

when they were at their most vulnerable.

Doggerland would have been particularly effected by this

because it is so low lying.

Even though it was about 130km across,

and perhaps 80km north to south,

the average height was probably on the order of metres

rather than tens of metres.

So if you have a wave that is 5m high,

it is obviously going to inundate a large proportion of that land.

And if we look to modern events like the Japanese 2011 tsunami,

the average height there is around 5m.

The wave inundated up to 4km in land,

so if you think of that kind of scale,

you would have seen something similar happening at Doggerland.

The coastline is exactly where we would have seen

the majority of people.

The tsunami would have laid waste to homes, fish traps going,

hunting grounds disappearing.

Whole societies were perhaps wiped out

in the space of a few hours.

For Doggerland, it could have been cataclysmic,

covering most of the land in its fast moving water.

Many of those Doggerland people could have been washed away

along with their homes.

From the archaeological record, we do get a sense that actually

the tsunami is the beginning of the end,

if not the end of Doggerland.

And large swathes of it already underwater,

and what remains would have been quite significantly devastated

for some time.

Death as a great wave swept through Doggerland.

Doggerland still occasionally gives up its human evidence

from beneath the sea bed.

In 2019, a hammer stone was dredged up

from the drowned land.

But the Bradford team concluded that with rising sea levels,

Doggerland, the land that connected all of northern Europe,

would have sunk under the sea...

..ending all human life.

The Storegga tsunami was a difficult period for the Mesolithic people,

but the land did recover.

However, after that period, sea level continues to rise,

the landscape continued to shrink and break up into different islands,

so the challenges increased for people.

And so really it's part of the beginning of the end.

Eventually people would have found it

perhaps too difficult to live in certain places and moved.

As of today,

scientists are yet to find any artefact

from the Doggerland area that dates after the tsunami.

We don't find any human artefacts after this wave,

so there is absolutely nothing

that dates from younger than 6,100 BC,

which just shows the devastation this wave probably caused.

The tsunami's devastation seems total.

Doggerland...

..a Mesolithic paradise that supported human populations,

animals, forests,

and wetlands.

A land that at one point

is estimated to have stretched from what today is northern Europe,

to Scandinavia

and the UK,

covering almost 50,000 square kilometres.

Hunter-gatherers of the time

could have walked from present day Berlin...

..to Oslo...

..to London...

..to Paris.

A region that in the space of possible only a few hundred years

was completely swallowed by the sea,

drowning everything that lived on it.

An ancient apocalypse which echoes through human history,

through the myths and legends of great floods...

..and still touches us today.

The Bible.

It's one of the most influential texts ever written.

For millennia, it's shaped the lives of billions of people.

It holds stories of great civilisations.

Miraculous events.

The word of God.

Many people see them as parables for how to live their lives.

But for some, these stories are historical truth.

Of all the events the Bible details,

one remains shocking even today

- the destruction of Sodom.

According to the Bible,

Sodom was one of the five cities of the plain.

It was remarkable for its wickedness.

The tradition is that the sin of Sodom

was what the Bible described to be sexual perversity.

Specifically homosexuality.

But is this really true?

In the Bible story, God appeared before Abraham

and told him his plan to destroy Sodom

and the cities of the plain.

For Abraham, it's a shocking revelation.

His nephew Lot lived in Sodom.

According to the Bible,

Lot and his family were different than the other people

living in Sodom.

They would be considered righteous people.

Abraham pleaded with God not to destroy

the innocent and guilty without distinction.

God assured Abraham that he would spare the city

if just 10 decent people could be found there.

And devised a test of Sodom's hospitality to strangers.

The Bible says specifically

that the sin of Sodom was arrogance, gluttony and apathy.

And specifically that they were not kind

to the poor and the needy.

That it was inhospitality,

this general unkindness towards other people

that made Sodom an evil city.

God sends two angels disguised as travellers to meet with Lot

who takes them in and treats them well.

Lot passes God's hospitality test.

But when the news of the foreigners arrival

spreads through Sodom,

the city descends on Lot's house

and demands he hands them over.

Immediately all the neighbours are banging on the door

saying, "Send out these two men so that we may know them."

And in biblical terms,

that usually means to sleep with them.

Lot says, "Absolutely not, you can have my daughters instead.

"They're virgins, you can do whatever you want with them.

"But you cannot have my guests."

At that point, God steps in

and says, "No, the test has failed."

It's damning.

The angels allow Lot and his family to leave,

but when they are gone,

God levels the city with the remaining inhabitants inside.

It would've been positively terrifying.

WOMAN: God destroyed them in a shower of fire and brimstone

so terrible that no man could live in this land.

The destruction was so complete

that the city was abandoned for 700 years.

It's a profound punishment for the city's perceived sins.

God sends these two angels down

to Sodom and the cities of the plain

to test their hospitality,

to see 'would they be welcomed?'

and they failed that test.

So it's less a story about sexuality

and it's more a story about hospitality.

Hospitality was so important in the ancient world.

Only after the rise of Christianity

in the first few centuries CE,

did its interpretation change.

Early Christian theologians

shifted the story's focus away from offering hospitality

to create a morality tale condemning homosexuality.

But does the story of destruction hold any truth?

We ask the question did the city of Sodom actually exist

and could it be possible to locate its ruins?

According to the ancient writings of the Bible,

the Koran, and the Torah,

Sodom was supposedly part

of what's known as the five cities of the plain.

They were situated in southern Canaan

a large region covering modern-day Jordan,

Lebanon, Syria and Israel.

Of the five cities, Sodom was the largest

and thus, the epicentre of the plain.

For centuries, archaeologists have tried to locate it.

I think everybody loves a good lost city story,

whether it's Atlantis or Sodom,

there's this treasure-hunter aspect to it.

There's a confirming mythology,

a way of confirming the historicity of oral tradition.

But if the story of Sodom is more than just a myth

like some believe,

where did it take place?

And how could archaeologists locate it?

Renowned biblical archaeologists

Dr Thomas Schaub and Walter Rast

carry out surveys of Bab edh-Dra.

It is an ancient site south-east of the Dead Sea.

Thomas Schaub and Walter Rast

were actually very well-respected archaeologists

and academics in the field.

Both had a keen interest in biblical archaeology,

and historical geography.

Schaub was actually a priest

and Walter Rast led many expeditions to the Dead Sea.

As the two break ground, they discover

four more sites nearby.

Numeira, Safi, Feihfeh, and Khanazir.

For Schaub and Rast, the number of sites

could be a crucial indicator for whether Bab edh-Dra is Sodom.

The Bible says that Sodom

was one of five cities of the plain.

And if four other cities were discovered near Bab edh-Dra

it increases the likelihood that Bab edh-Dra

is the city of Sodom.

The discovery of these five ancient sites

in close proximity to each other is key.

And through excavations of Bab edh-Dra,

the archaeologists date the site to around 3300 BCE.

This is significant because some people think

this is when the city of Sodom existed too.

And during excavations, the team unearth evidence

that not only was Bab edh-Dra the largest of the five sites,

but it was also once

the location of a thriving community.

There were fortification walls around the town.

Archaeologists were able to identify people's houses.

Workshops. It would've been a place of some significance.

For Schaub and Rast, it's looking more and more likely

that Bab edh-Dra is Sodom.

And when the archaeologists examine the site more closely,

they make a crucial discovery.

There is evidence of widespread destruction.

The archaeologists discovered piles of collapsed mud bricks

and also large piles of ash and charcoal.

And the town walls had been destroyed by fire.

At the second site, Numeira,

Schaub and Rast make similar findings.

But most astonishingly,

archaeologists find the skeletons several people.

The bodies were buried under all of this burnt debris.

So these were people who had died and been crushed

while they were still either fresh corpses

or while they were still alive.

Some experts believe that Schaub and Rast's findings

match the biblical description of the destruction of Sodom.

Through fire and brimstone.

There is one camp who think that Bab edh-Dra and Numeira

are evidence of destruction from an earthquake

and catastrophic fires.

That we've found our target.

The claim, that the southern site of Bab edh-Dra

could be the former city of Sodom

becomes known as the Southern Theory.

But had biblical Sodom finally been uncovered?

Over the years, new evidence has emerged

which casts doubt on the theory.

When excavations were carried out

at the other three sites,

archaeologists found

that there were no occupational structures.

What they had found was a bunch of cemeteries.

This is a place where people buried their dead.

And radiocarbon dating of the two largest sites,

Bab edh-Dra and Numeira

Cast further doubt on the Southern Theory.

These two cities were destroyed

2.5 centuries apart from one another.

That's 250 years in between

the destruction of Bab edh-Dra and Numeira.

To match the biblical description,

these sites should all have been destroyed at the same time.

They don't fit the time

so yeah, to me, it's two strikes and you're out.

You don't need a third strike.

The Southern Theory just does not hold water.

Did Sodom ever exist?

If so, was it at all possible to find?

In 1996, archaeologist Dr Steven Collins

takes up the challenge.

Having grown up in a Christian household,

he has long been fascinated with the relationship

between the Bible and scientific evidence.

I had sort of worlds in collision going on in my head.

And it was hard to justify

science and faith and belief together.

Joining Dr Collins in the search for Sodom

is Dr Philip Silvia.

An electrical engineer by trade,

in more recent years,

he's turned his focus to the Bible and archaeology.

I think Sodom is the epitome in Scripture

of God's judgment against sin in the world.

It's the engineer in me.

And the theologian in me

understands there must be a discoverable trail

of physical evidence showing us what he did and how he did it,

and that's what drives me.

The more Dr Collins studied, the more convinced he became

that the Bible could provide clues to the location of Sodom.

And so when I look at the historical record,

when I look at the biblical record,

and it squares with reality, it's worse with science,

it squares with archaeology,

and I can't find any way to overturn it,

then what are supposed to do?

For Dr Collins, the realisation that Sodom

and the cities of the plain

may not be south of the Dead Sea

came about by accident in 1996.

That summer, he is leading a tour of the holy land sites.

While planning an expedition to Bab edh-Dra

and Numeira, he rereads the story of Sodom -

something is amiss.

In the Bible, before Lot moves to Sodom,

he and his uncle Abraham bid farewell to each other.

At this time, the Bible places them somewhere between

the settlements of Bethel and Ai.

North-west of the Dead Sea.

From there, they can see the whole plain of Jordan.

The Bible says, "Lot looked over,

"saw the well water play into the Jordan

"and went eastward and pitched his tent as far as Sodom."

According to the Southern Theory,

Sodom is south-east of the Dead Sea.

80km from Bethel and Ai.

But if Abraham and Lot were in the North

at Bethel and Ai, they wouldn't have been able to see that far.

I got to the end of it and I thought to myself,

"I don't see anything in there

"that would locate Sodom towards the south

"but everything would locate it

"north and east of the Dead Sea."

How in the world could serious scholars

be putting Sodom towards the south end of the Dead Sea

because if they're reading the same text I'm reading,

what aren't we seeing the same things?

Collins digs deeper into the ancient text.

His focus turns to identifying

the correct location for the plain of Jordan.

Genesis 13:10 says that

Lot saw the plain of Jordan

and that it was well watered like the garden of the Lord.

So if you can find the plain of Jordan, you can find Sodom.

After meticulous study, Collins finds a clue to the whereabouts

of the plain of Jordan.

In the Hebrew language, the word for 'plain' is 'kikkar'

which means 'round'.

In the case of land, it would be a round, flat area

of arable land.

That is where we should be looking

for Sodom and the cities of the plain.

Some archaeologists believe that the only area in Jordan

that has a flat, circular plain

and is well watered is north of the Dead Sea.

If you are looking at a very good topographical map,

you'll see a circular area, a kikkar,

north of the Dead Sea.

But for some, using the Bible

as a geographical source should be approached with caution.

We need to be cautious with how we use the Bible texts.

We have to keep in mind that if this event happened,

it was another thousand years before it was written down.

And then since being written down,

it's passed through five, six, seven different languages

before it comes to us.

So to put too much weight on one word is a bit hazardous.

If we treat Sodom and the cities of the plain

as a crime scene, then the Bible is one source.

We also have archaeological evidence, we have ancient maps,

so we have to actually look at the whole thing like a puzzle.

And each piece has to be put together

to really grasp what happened there.

Proponents of this new northern theory

are convinced somewhere in this circular plain

could lie the biblical city of Sodom.

Further evidence may lie

in the oldest surviving map of biblical sites,

the Madaba Map.

It dates from the sixth century CE

and is located in the Byzantine church of St. George

and Madaba, Jordan.

We have to understand that the Byzantine period

was the biggest holy land tourist industry

ever in history

and so this map was on the floor of this church

for the singular purpose of showing people where to go.

The map is incomplete

but crucially, it features a key name, Zoar.

Along with Sodom, the Bible

lists it as one of the five cities of the plain.

Zoar is significant because it was

the only city of the plain that wasn't destroyed

and it wasn't destroyed according to the Bible

because it was the city

to where Lot and his family escaped.

The map doesn't feature Sodom

but it does feature something else north of the Dead Sea.

Partially intact depictions of two cities.

For Dr Collins, they're key geographical markers.

I have a sneaking suspicion

that those two representations of cities

on the north end of the Dead Sea are Sodom and Gomorrah.

But if the missing piece of the map is Sodom,

where exactly is it?

In 2005, Collins and his colleagues head Jordan

in search of hard evidence.

And that was a little bit scary at first

because I couldn't find any map of archaeological sites

done by anyone in America or Europe or Israel

and it really bothered me.

I said, "What I might gonna find when I get over there?"

But then, at the American Center of Oriental Research,

a breakthrough.

As the team pore over maps and surveys,

they come across a book,

'The Antiquities of the Jordan Rift Valley'.

In it is a map showing ancient sites

in the Kikaar region of Jordan

north-east of the Dead Sea.

The team put boots on the ground

and begin a process of elimination,

hoping to identify the most likely site for Sodom.

And what did we find? 14 major archaeological sites.

Well, here was the problem.

I was only looking for four or five sites. Now I had 14.

Some seem to be too small, too insignificant

or the wrong period.

So we eliminated them.

After a week of surveying, only one candidate remained.

Tall el-Hammam.

It's situated 13km northeast of the Dead Sea.

The Bible had told me that Sodom should be

the biggest Bronze Age city

on the north-east side of the Dead Sea.

Guess what? It was just absolutely huge.

How in the world had people not put this on their radar?

Why was it not on any map?

After almost a decade of research, Tall el-Hammam

is Collins' prime suspect for Sodom.

I was walking down on the top of Tall el-Hammam

and I grabbed a handful of that sand

and sort of let it run down through my fingers.

And I said, "Someday you're gonna tell me what you know."

But to reveal the truth behind this ancient site,

he needs to start digging.

On December 27, 2005, the team begin the excavation.

Initial findings reveal a colossal site

spanning an area of approximately 150 acres.

It's much larger than any other Bronze Age site in the region.

I was surprised -

I think mostly the sheer size of the site.

To me it was just an 'oh, wow' moment.

With the site larger than anyone had anticipated,

Collins recruits world-renowned archaeological architect

Dr Leen Ritmeyer to map the site.

I got a phone call from Dr Steve Collins

and he said, "Would you like to come to Jordan

"and see my new excavation site?

"I believe I found Sodom."

I said, "Sodom? You must be daft. It's quite impossible."

He said, "Just come and have a look." I said, "OK, I'll come."

This is site and the architecture

impressed me very much.

And so I was really interested

in the site from an archaeological point of view.

During the first few seasons of the excavations,

the team unearth fortified walls 5m thick.

And up to 12m high.

They also found a palace, a temple,

and at least two plazas and dozens of houses and streets.

All dating to the middle Bronze Age period

when Sodom is believed to have existed.

The middle Bronze Age

fortifications were stunning to me.

We estimate the rampart system itself

took somewhere between 40 and 60 million mud bricks to make.

It was obviously a highly centralised government

who could put such a project together and complete it.

I've worked on many archaeological excavations.

To have never seen

such a huge site as Tall el-Hammam...

About six times as big as the old city of Jerusalem.

Crucially, the team discover layers of ash throughout.

Ranging from half a metre to 2m thick.

Evidence that Tall el-Hammam was destroyed.

And they're convinced it was destroyed

in the middle Bronze Age.

Mixed in with that ash are pieces of pottery

that we can identify with that middle Bronze Age date.

The evidence indicates the site was burned in 1700 BCE.

And as Dr Silvia sifts through the ash layer,

a picture of a great destructive event emerges.

Among the ruins, they felt find a large 180kg saddle quern

that workers used to grind grain.

It's called a saddle quern

because you would basically would straddle it

like you were riding a horse and then you would

run your grinder back and forth like this to grind the grain.

But for Dr Silvia, the position of the saddle quern

doesn't make any sense.

It was literally blown off of its dirt pedestal

onto its side on the ground

in a north-easterly direction.

The team are intrigued by how such a large, heavy object

could have been blown over.

And it's not the only object.

Across the site they uncover artifacts and structures

that landed in the same direction,

seemingly pushed by some catastrophic force.

You find bits and pieces of pottery.

Everything you can imagine

strewn for six, seven, eight metres

across the floor to the northeast.

So everything has this directionality to it.

Everything inside there is churned up and full of ash

and pottery and broken mud bricks.

And everything about it is catastrophic.

The team has uncovered evidence of a great destructive event

hitting Tall el-Hammam.

Dr Collins calls it the Middle Bronze Destruction Event.

What could've caused it?

In 2011, the team make a chilling find.

We start finding human bones,

piece of a pelvis, piece of a kneebone.

Piece of a femur.

One of them was only existing from the mid-femur down.

Everything else is missing.

And the place where the separation occurred

is severely burned,

it's almost like they were burned off.

They appear to have been bodily slammed up against

one of the very thick walls

and then fell to the ground

and were covered in ash and in material there.

These were not lovingly placed burials.

These were people who wound up in these positions

by some sort of violent event.

In another section, they find further evidence

that the inhabitants were killed by an intense force.

In the Middle Bronze Palace area, two skulls emerged.

We have no lower jaw bones on either one.

One we have the entire skull and it is smashed down.

One has a piece of pelvis right here

next to the fragments of the skull.

They are literally blown to bits.

For Collins, the location of the skulls is key.

We are 8m down and a meter deep

in the destruction matrix.

There is no doubt, zero doubt

that these two individuals,

these two skulls' fragments

belong to the Middle Bronze Destruction Event itself.

The body is just not designed

to stand up to that kind of force

and it's both shocking, it's both traumatising

but on the other hand, as an engineer,

as a scientist, it's absolutely fascinating.

The team believes they are getting closer to discovering

what destroyed this city.

But so far, nothing conclusive

which tells them this might be biblical Sodom.

But the more they excavate, the clearer it becomes

that they are dealing with a monumental site.

Along the outside of the city,

they uncover the foundations of a much larger structure.

A 3m-thick wall.

We asked them to dig a bit to the further to the east

and I found the beginning of another wall coming out,

same type of bricks.

And as the other one was 3m wide, I kind of paced it out.

But then it clicked to me, we've got here a massive tower

extending out from the city wall.

Dr Ritmeyer and the team have just come across the ruins

of a colossal gateway complex.

21m wide, and 14m high

with towers on either side and up to six chambers.

The Tall el-Hammam Team

are gradually unearthing the secrets of a vast metropolis

spanning an area approximately 150 acres

with an estimated population of up to 65,000 inhabitants.

It had all the features of a major, major city centre.

With its palaces, its temples, its residential areas,

its streets, its massive fortifications,

its satellite towns, its massive agricultural areas

that it could take advantage of.

It had everything to make it great.

And this is what the Bible describes

and this is what the archaeology confirms.

If fits the geographical clues in terms of location,

it fits the timeframe in terms of its occupation history.

To me, I don't see what other conclusion you can come to.

But if they want to convince the wider community

that Tall el-Hammam is biblical Sodom,

then their work is far from over.

I have to say the site is really interesting.

It's the interpretation of the site that I find problematic.

So much more work needs to be done

before we can understand the site.

The site in context and its importance.

But also, what destroyed it.

Whether or not Tall el-Hammam is Sodom remains to be seen

but what's clear from the team's findings

is there once existed a large and thriving civilisation

in this area.

In Tall el-Hammam,

we got a very definite layout of the city.

Then you got the lower city and upper city.

The lower city where the common people,

and you had the upper city

which had its own separate defence system.

It was a totally secluded area

used by the King to have his palace and his royal officials.

Artifacts found throughout Tall el-Hammam have

helped the team decipher how people lived during this time.

Most of the houses are mudbrick houses.

And the houses themselves are often multigenerational houses.

You've got quite a few rooms

built around a central courtyard.

They had an awning overhead and that's where they baked bread,

where they roasted or chickens or whatever they were eating,

and the women used to grind the flour.

All that took place in the courtyard.

That was the kind of the life of the house.

We have a city that lasts for 3000 years without a hiccup.

Things are pretty much operating

like a well-oiled machine.

But then, according to the evidence,

somewhere around 1700 BCE,

during the Middle Bronze Age,

the city of Tall el-Hammam was violently destroyed.

What was behind its catastrophic demise?

Could the answer provide a clue

as to whether this is the original city of sin?

At the site, archaeologists have found evidence

of scorched walls and floors buried beneath piles of ash.

Burned pottery shards, as well as charred human remains

they believe were blown around by some concussive force.

For them, the evidence matches the biblical account

of fire and brimstone destroying Sodom.

But what could cause this?

If you're looking at evidence from Tall el-Hammam

it's reasonable to wonder

whether this is a consequence of a huge volcanic event.

Was Tall el-Hammam destroyed by a volcano?

In recent decades, experts have found evidence

of a volcanic flow of ancient lava

in the hills northeast of the Dead Sea.

Whilst 1/6th of Jordan is covered in hardened lava,

known as basalt.

MAN: There's lots and lots of basalt rock

in that part of the Dead Sea.

That's because that area is very geologically active.

Its had volcanism throughout much of its history.

But there is a problem with the theory.

There's no volcano close to the site of Tall el-Hammam.

To get volcanic activity, you don't need to have

a triangular volcanic mountain spewing out lots of lava

or even a dormant volcano,

what you need is a heat source underneath the surface

with molten rock

and you need pathways to the surface

by which that heat can get out,

and that's what we call a volcanic system.

So you can have a volcanic systems that are not invisible

but they're pretty hard to detect.

Despite evidence of ancient lava-flow in this region,

many reject the idea that this is responsible

for the destruction of the site.

There's just not enough of the material, you know?

You'd need a really significant amount of ash

to really cause the abandonment of a city.

And from what we can see, there doesn't seem to be enough.

But there is another natural event that could be to blame.

Now, if somebody told me

"OK, I've got the city ruins

"and they've been collapsed,

"obviously the buildings have toppled down

"and there's lots of evidence of fire happening."

I'd have probably gone,

"That sounds to me like it's probably an earthquake."

So what happens to tectonic plates during an earthquake

is that you got these two plates and they're moving

but at the boundary between the two of them,

they're stuck, they're snagged,

there's friction and the stress builds up.

It builds up and builds up

until at some point, it can't take it any longer,

and it just moves, it displaces.

And that generates a whole lot of energy,

a whole lot of friction or heat and noise.

That's the seismic waves that grow

and that essentially is the earthquake.

Could an earthquake have made the ground drastically shift

and caused the collapse of Tall el-Hammam?

So when the fault line moves, it can move vertically

or it can move horizontally,

or it can move a combination of the two.

And in the Dead Sea rift zone,

it tends to be a combination of the two.

That's what shook the buildings,

caused them to collapse

and maybe set off a chain reaction of fire,

maybe a kiln was on,

the rest of the roofs in the city burned,

and that's what had happened.

But for the Tall el-Hammam team,

the evidence they found at the site

suggests an earthquake can't be to blame.

When you got earthquake, the ground moves back and forth.

We are in a north/south strike slip zone

in the region around Tall el-Hammam

so when you have earthquakes there,

things tend to move north and south.

And so walls tend to fall in both directions

but all of the material evidence we're finding

is pushed to the north-east.

And only to the north-east.

It's very mono-directional.

Crucially, the team make another discovery

which suggests that the site remained unoccupied

for approximately 700 years

during the late Bronze Age period.

In that region, one of our primary means of telling time

is through pottery evidence.

We just do not have pottery in the region

that covers the entire late Bronze period.

There's virtually none.

And the second thing that you would look for is

is there any architecture?

There was a brief single building that we believe

was a toll house or a waystation

during that period

that lasted maybe a decade or two.

So between the pottery, between the architecture,

nobody was home.

They just migrated through.

The team have uncovered evidence

of a thriving middle Bronze Age city,

destroyed by a violent event,

followed by a 700-year period

where the site remained largely abandoned.

For them, the location of Tall el-Hammam

and its scale indicates it could be Sodom.

But they are no closer to explaining

the cause for its catastrophic demise.

Then, in 2011

whilst excavating a section of the upper city,

Dr Collins' team make an extraordinary discovery.

When the excavators of that square called me over,

they said, "You have to come and look at this."

They found a piece of pottery in the middle Bronze Age layer.

Thousands are scattered throughout the site.

But this piece is different.

On one side, the fragment looks like regular Bronze Age pottery,

but on the other, the surface is green and glasslike.

It looks like one side of it is superficially melted,

it's just lapping over the edge ever so slightly.

For Dr Collins, it looks like a piece of glazed Islamic pottery.

But this form of pottery wasn't produced until

thousands of years after the destruction of Tall el-Hammam.

Collins is intrigued by the find.

The fragment looks as though

it's time-travelled from a later era.

What in the world is a piece of glazed pottery

doing down here this deep?

Could it offer any clues

for the cause of Tall el-Hammam's destruction?

Collins takes the strange-looking piece of pottery

for analysis at the US Geological Survey Laboratory

in New Mexico.

When the results come back,

they are quite literally out of this world.

We know that now from the tests

everything about this melted surface of pottery shard

is physically identical to trinitite.

The word 'trinitite' comes from the codename

'Trinity' using the first ever detonation of a nuclear bomb.

The test took place on 16 July, 1945

in the Jornada del Muerto Desert, New Mexico.

When the Trinity bomb was detonated,

it released the equivalent of 21,000 tonnes of TNT.

That's actually slightly more than

the nuclear bomb they dropped in Hiroshima in WWII.

In the aftermath of the explosion,

scientists noticed a strange substance

all across the surface of the desert.

When the bomb exploded, it sent out a big fireball

and that creates a huge mushroom cloud,

a big up-rush

and it took a whole load of the sand up in there

and that basically melted

because of the immense heat,

and then rained back down onto the desert

which cooled really quickly

and then formed this glassy trinitite.

The melted glasslike surface of the sand

is similar to that found on the pottery shard at Tall el-Hammam.

When it's analyzed further, experts discover something else.

Zircon.

Zircon is a naturally occurring mineral

that you can find in rocks pretty much all over the world.

Looking at zircon under a microscope,

what you'll see is a crystal-like structure

and very regular with very sharp, jagged edges, basically.

But the zircon inside this piece of pottery is different.

This zircon was actually a lot smoother, more like a teardrop.

Experts conclude that the zircon in this fragment

must've undergone an extreme process

to create such a strange shape.

It suggests that this zircon

had been heated up to a really high temperature

such that it even melted and then it cooled very quickly,

because otherwise you get the more regular-looking zircon

that usually takes thousands of years to cool down.

The fragment must have been subjected to extreme heat

for it to have melted this way.

A normal fire will burn at somewhere between 602,000°C.

For zircon to melt, though,

you're talking at least 4000°C there.

That's over double the hottest fires.

Now, the surface of the sun is about 4000°.

So you're talking about temperatures

equal to the surface of the sun.

And as the excavation continues,

the team unearth more and more pieces

of extreme heat-blasted pottery.

Every place we've excavated across the site,

we have found indicators of these high-heat events.

Every place we find bits and pieces.

What kind of thing could do that?

From the evidence at this ancient site,

we know there must have been incredible temperatures,

much hotter than a regular fire.

And it created a substance very similar to trinitite,

but of course there weren't nuclear bombs back then

so what could've caused this?

Well, one possible option is a meteor.

Now, at our site, there is no crater on the ground

for us to point to and look at and say. "Ah-ha!

"Here's the conclusive evidence that we had

"some kind of astral body coming in and hitting us."

We don't have that.

But meteors don't need to make impact

to unleash their destructive power on earth.

An incredible concussive force

and a blast of high-intensity heat

can result from a rare cosmic phenomenon

known as a meteor airburst.

An airburst can be

when a meteor in the Earth's atmosphere

explodes in the air before it's hit the ground.

The damage on the ground from the explosion

can be devastating.

Firstly, you've got this really hot rock,

the meteor, in the air,

that's radiating heat

that can set things ablaze.

Now, when it explodes, you've got the big shockwave,

and that can also take temperature with it,

so you can feel a heat rush.

The amount of devastation you're going to see

really depends on the size of the rock.

Bigger meteor, more destruction.

Meteor airbursts are rare

but they have occurred in recent history.

In 1908, in a remote, uninhabited region of Siberia,

and airburst is believed to have wiped out an area

larger than Los Angeles.

An eyewitness described the sky appearing to split into,

and being covered with fire.

It destroyed about 80 million trees.

In the nearest town, about 60km away

residents could feel the heat of the blast,

windows smashed and the buildings

and some people were even knocked off their feet

because of the force of the airburst strike.

It would have felt like the end of days.

More recently, in 2013, cameras caught the moment an airburst

exploded over the city of Chelyabinsk in southern Russia.

1500 people suffered injuries

and thousands of buildings were damaged.

The team at Tall el-Hammam

believe that the evidence they found points to an airburst

which left a path of destruction in its wake.

What we're looking at is a very large site

that was literally

the buildings blown off of their foundations.

Artefacts, the pottery, the tools that they were using

are shattered and this basically

vaporises and incinerates everything in its path.

And what we see is that all of that ash

and all of that material is blown

into a north-easterly direction.

The only known source of the kind of concussive profile

that we're seen in the evidence

of the kind of thermal profile

that we're seeing is a meteoritic airburst.

As for the 700-year gap in habitation at Tall el-Hammam,

Dr Silvia leaves this is the direct result of the airburst

as it explodes over the Dead Sea, just 13km away.

If you have an airburst event over water,

it will actually produce a tsunami effect

where a wave will be pushed across the landscape.

You have a very high volume of now superheated brine spray

of Dead Sea water

that's travelling with the blast front,

well, that 700-year gap I believe is best explained

by the poisoning of the soil with Dead Sea water

that left behind a very high salt concentration.

It's possible the high salt content of the Dead Sea water

would've rendered the land infertile

for a number of centuries.

It was impossible to grow any cereal grains,

and if you can't grow cereal grains,

you can't support cattle, you can't support people,

you just cannot support a civilisation

moving back into the area.

The science is clear, the analysis is clear.

And the evidence is mounting.

I'm not saying

that we absolutely have it nailed down yet,

but we know that all the indicators that we have

are consistent with and airburst.

For the archaeologists, the destruction of Tall el-Hammam

by meteor airburst

provides a striking match

to the biblical destruction of Sodom.

Fire and brimstone rained from above,

destroying the city and its people,

leaving the surrounding region uninhabitable.

But not everyone is convinced.

A meteoritic event is very rare.

They do happen but they're very rare.

I think before you can jump to conclusions

and people can start suggesting that,

you need more evidence,

and I think, actually, an event like that would

have a signature much wider and in the environmental record,

so we need to look there.

Since 2005, Dr Collins and his team

have excavated at Tall el-Hammam.

They've made a truly astonishing find,

the remains of a thriving, vast metropolis

north-east of the Dead Sea,

which they believe matches the biblical description of Sodom.

Crucially, for Collins, the discovery and analysis

of Tall el-Hammam's destruction

provides a close match to the biblical account

of the destruction of Sodom.

People often ask me how certain I am

that Tall el-Hamman is Sodom.

It's become very certain to me

that there is no other possibility.

It's in the right place, it is in exactly the right timeframe,

it has the right stuff, it has the right destruction event.

When Steve Collins first asked me to come to the dig

and he said that he thought that this may be Sodom,

I was very sceptical.

I believe the Bible, I think that that's serious.

But I don't dig with the Bible in my hand, as it were.

The size, the location, the way Sodom was destroyed,

and my own reading again, the original text,

made me now convinced that Tall el-Hammam is Sodom.

But the team still face scrutiny

from the wider archaeological community.

We know that meteorites strike the earth

so is this possible? Sure.

Is this is also a pretty speculative reaching

for a possible explanation

that kind of matches the story in the Bible

to explain the destruction of what you want to be Sodom?

Yeah, it looks like that as well.

Cynics want to suggest that the airburst theory

for the destruction of Tall el-Hammam

is just too spectacular, too kind of space-age.

But just because it's a one-in-a-million chance

doesn't mean that it didn't happen.

The team continues to dig for evidence.

To answer the question beyond doubt,

of whether Tall el-Hammam

really is the city of Sodom.

Ancient Greece.

From the 8th century,

until the 4th century BCE,

ancient Greek civilisation flourished.

It gave the world democracy,

philosophy,

and art and architecture

that still dominate our lives today.

At its height,

the ancient Greek colonies

reached from modern day Spain in the west,

through to Russia in the north and Egypt in the south.

It was made up of many competing city states,

with their own systems of rule and patron gods.

In the heartland of this civilisation,

lay the thriving city of Helike.

Helike was a prominent trading pulpit.

But the ancient city was best known

for the role it played in the worship,

of the almighty Poseidon,

the god of the Sea.

Poseidon's moody, he is miserable.

He's grumpy.

And I find that really interesting

because he is the god of the Sea.

And the sea is obviously important for trade,

important for transportation,

but it can turn on you like that.

And can take lives.

It's something Helike would discover all too well.

In 373 BCE,

the city vanishes.

According to writers across the ancient world,

the entire city disappears beneath the waves.

Its location is lost to the passage of time.

The location of Helike is a complete mystery.

And it's one of the resounding mysteries of classical archaeology.

It's hauntingly similar to the myth

of another ancient civilisation lost beneath the waves -

Atlantis.

We asked the question,

what could cause the total destruction of Helike?

And is Helike, Atlantis?

The Lost City of Atlantis.

It's a myth that has enthralled us for millennia.

We all know the famous story of Atlantis.

But it goes all the way back to Plato,

who tells us about Atlantis

as a great city with an advanced civilisation,

which ruled over an empire that spanned continents.

According to Plato's myth,

the Atlanteans created a civilisation to rival the mighty Greeks.

But they did not use their power wisely,

and this angered the gods.

The Atlanteans grew cruel, they grew harsh,

they grew hubristic.

And for this, they were punished by the gods.

The city was destroyed and submerged,

and lost beneath the waves.

For centuries, it's driven explorers to search the seafloor.

Uncovering shipwrecks, lost treasure.

But none have found the fabled lost city.

It's even eluded famed oceanographer Jacques Cousteau,

who led underwater expeditions in search of Atlantis in 1975.

But there is another lost city

mentioned by classical Greek historians

that may offer clues - Helike.

Just like Plato's myth of Atlantis,

these authors record how Helike was submerged beneath the waves.

If we look at the story,

Helike and Atlantis,

both were disappeared

from the face of the Earth.

They both disappeared into waters.

Helike and Atlantis also share

the same patron god, Poseidon.

And Plato wrote the story of Atlantis around 360 BCE,

just after Helike was destroyed.

Could Helike actually be Atlantis?

The only way to know for certain,

is for archaeologists to locate

the lost city of Helike.

In the 4th century BCE,

a period of time known as The Classical Period,

the ancient Greek city state of Helike

thrived on the shores of the Corinthian Gulf.

It's a city with a rich history.

The first time we ever hear about Helike,

it's in Homer's 'Iliad'.

The classic Greek myth, 'The Iliad',

tells how Helen, the Queen of Sparta,

was abducted by Paris of Troy.

Agamemnon, the King of Mycenae,

commanded the united Greek armed forces

and set sail to bring Helen home.

Helike's listed amongst the many cities

of the Peloponnese

which send troops

for Agamemnon's army to campaign in the Trojan War.

Agamemnon's forces besieged Troy for ten long years.

When this failed,

they unleashed their secret weapon, the Trojan Horse.

This giant wooden horse was left as a gift for Troy.

They accepted it

and brought it inside the city walls.

With the people of Troy asleep,

Greece's finest soldiers

emerged from inside the horse and opened their gates.

Agamemnon's forces could finally breach the city's walls,

and Troy fell.

Homer's 'Iliad', is a myth.

But Helike's role in ancient Greek history

is well documented.

Helike was the leader of the Archaean League,

a democratic confederation of 12 city states

in the Archaea region of Greece.

Helike established colonies at Priene in Asia Minor,

and Sybaris in southern Italy.

Trade from these created a period of great prosperity.

The people of Helike believed their city

was watched over by their patron god, Poseidon.

Their temple dedicated to him

brought pilgrims to the city from across Classical Greece.

Helike was a power house

in the ancient Hellenistic Greek world.

It was a major religious hub, a pilgrimage spot.

It was a political seat.

It was a pretty significant city state.

The temple to Poseidon gave Helike influence in the Greek world,

and they benefited economically from this pilgrimage.

As war engulfed the region,

it placed Helike in a unique position.

Between 492 and 479 BCE,

the Persian Empire launched a series of invasions,

with the aim of conquering all of Greece.

The allied efforts of the Greek city states repulsed the Persians,

but the Greek world was now on a collision course with itself.

In 431 BCE,

Greece erupted in war between Athens and Sparta.

By 404 BCE, Sparta was victorious.

But the economic cost across the region was dire.

Poverty soon became widespread.

But the people of Helike realised

just how economically important

the Temple of Poseidon was to their survival.

They remained largely uninvolved throughout this period of turmoil,

for fear of alienating either side.

This decision served them well.

As the dust settled,

Helike and its colonies survived,

along with the Temple of Poseidon

and the income this brought them.

And for a city state that relied heavily on maritime trade,

it made sense that their patron god,

was the god of the Sea.

Poseidon is the god of the trade networks.

He's the god who the sailors

would be praying to

before they set out

on their long voyages across the Mediterranean.

He's the god who would guarantee you safe passage

and bring you back home safely as well.

But Poseidon didn't keep the people of Helike safe.

According to the legend,

the people of Helike closely guarded the temple, venerating Poseidon.

When they refused to share secret items with other cities,

he was angered.

They had treated extremely badly a sacred delegation

who had come from Ionia

requesting copies of the Altar

and some other sacred items.

They had dragged these sacred ambassadors from the sanctuary,

and some stories say they actually killed them.

In 373 BCE,

Poseidon destroyed the city.

The destruction was so complete

that it sent shock waves around the ancient world.

The story of Helike's demise

very quickly enters into the popular conscience.

We first get it in the writings of Ephesus,

we find it in Strabo, we find it in Ovid,

we find it in Pausanias and Diodoris and Polybius,

it's everywhere.

The story starts in 373 BCE,

and we hear that Poseidon

is angry with the inhabitants of Helike.

And what he does is he uses his trident,

he causes a terrible earthquake.

A tidal wave rolls in from the sea

and completely submerges the city.

The entire population of Helike was wiped out in this catastrophe

in one fell swoop.

And not only that,

but there were ten Spartan warships which were anchored in the bay,

and they were also dragged down to the bottom of the sea.

So this was total wipe out.

Helike's destruction was so severe

that the only way the ancient Greek writers

could come to terms with it,

was to blame it on the supernatural -

Poseidon,

the god of the Sea,

caused the city to vanish beneath the waves.

In the years that follow,

its location is forgotten,

and the story of Helike becomes Greek legend.

The parallels between the myth of Atlantis

and Helike's destruction are striking.

But what actually happened?

And could Helike be Atlantis?

The only way to know is to find Helike.

For archaeologists to have any hope of locating the lost city

and determining what caused its destruction,

they need to discern

what is fact and what is fiction.

Was there any physical proof

that Helike had actually existed?

Two of Germany's leading archaeologists,

Adolf Michaelis and Alexander Conze,

explore the shores surrounding the Gulf of Corinth.

While resting in the village,

they are sold an ancient artefact,

a bronze coin.

Poseidon is depicted

in a very fine representation of his head,

which is a very beautiful, classical actually,

depiction of Poseidon.

And on the reverse we have the main attributes of Poseidon,

that is his trident

and the two dolphins swimming upwards,

all included in a wreath, within a wreath.

But as Michaelis and Conze examine the coin more closely,

they make a startling discovery.

The coin bears the letters, 'ELIK',

which is an abbreviation of, 'Elike', 'Helike'.

This was the first tangible piece of evidence

that the city of Helike actually existed.

Up until this point,

all we had was the testimony

of various authors and the story of Helike's destruction,

but this was an actual piece of evidence.

Michaelis and Conze have identified

the first piece of archaeological evidence

that Helike actually existed.

It marks an incredible turning point.

Was the lost city of Helike more than just a legend?

Could there be some truth behind its destruction?

And could it help solve the mystery of Atlantis?

Archaeologists need to re-examine

the ancient texts describing Helike's destruction.

Could they find anything else written here

that might help them sort fact from the legend?

A key text recounting the disappearance of Helike

was written in the second century CE

by the renowned Roman author, Aelian.

Buried in his account,

is a detail that may lend voracity

to the written destruction event,

a tsunami caused by an earthquake.

There's a Roman author

who talks about the destruction of Helike,

and he mentions that five days before the event,

all the animals, all the rats,

all the insects, went scurrying away from the site.

And the people should have taken that as warning

something bad was about to happen.

It's an intriguing detail.

But is there any truth to the phenomenon?

Geologist Ian Stewart has heard similar stories before,

an animal exodus right before a major earthquake.

In 1995 I was in northern Greece,

and we were starting to get reports

that there had been this earthquake down in the Aigion area.

I spoke to fisherman,

who talked about catching

the equivalent of their whole yearly catch

in the night before the earthquake struck.

And also in their catch,

strange fish that they hadn't seen,

deep water squid and things that were very rare.

And one of the things that we know

is the Earth's crust gets prepared for earthquakes.

The stress gets pent up

and there's fluids and lots of things change.

So the only slight thing

is whether animals,

particularly ground dwelling animals,

could be sensitive to that.

And that seems to be not that far from reality.

The story of animals fleeing Helike

in the lead up to its destruction

might just be true.

And according to the ancient writers,

the tsunami that submerged Helike

was triggered by an earthquake.

But would a tsunami account for its total eradication?

To know for certain, archaeologists need to locate Helike.

Only then, can they begin to understand

the cause of its destruction.

The hunt is on for The lost city of Helike.

They turn again to the ancient texts.

It's believed that the remains of Helike

were visible for hundreds of years

after it was destroyed,

and many ancient writers give descriptions of its location.

But over time its ruins disappeared,

and these descriptions lost their meaning.

The archaeologists searching for Helike

are forced to start from scratch, almost.

Pouring over the ancient texts,

they find a clue.

The ancient Greek geographer, Strabo,

recorded that Helike had been submerged

in what he describes as a 'poros'.

But what exactly is a 'poros'?

'Poros', in ancient Greece,

means a narrow passage of water.

Archaeologists interpreted this

as the Corinthian Gulf.

It was a solid lead

for the archaeological investigators.

The ruins of Helike had to be somewhere in the Corinthian Gulf.

The problem is, the Gulf encompasses a colossal area,

2,500 square kilometres.

And according to the ancient texts,

just like the myth of Atlantis,

the ruins should be underwater.

The expectation was that Helike lay

somewhere on the sea bed in the Gulf of Corinth.

And so over the generations,

it becomes this holy grail of underwater archaeology,

to find where Helike was.

Archaeologists now have a rough geographic area for Helike.

It's clear to them that it must lay submerged

at the bottom of the Gulf of Corinth.

But how can you locate a lost city on the seafloor?

It would require an entirely new form of archaeology,

and a new breed of archaeologist.

The hunt for the lost city of Helike

is taken up by one of Greece's most famous sons,

celebrity archaeologist Spyridon Marinatos.

In 1967,

Marinatos became a Greek national hero

when he uncovered the prehistoric city of Akrotiri,

on the island of Santorini.

For some, the civilisation on Akrotiri

was a strong contender for the lost city of Atlantis.

But Marinatos found no evidence

to back up this theory.

And his ultimate dream was to find Helike.

If the lost city could ever be located,

Marinatos had particularly high hopes

for what it might contain.

He believed that Helike

would be a kind of a Greek classical Pompeii.

That is, everything you would find

in Helike would be there,

exactly as it was

at the moment it was destroyed.

If he could find the city,

maybe he could solve the mystery of its destruction.

Could he also solve the mystery of Atlantis?

Marinatos needs a way of peering beneath the waves

to identify any human made structures on the sea bed.

He turns to a cutting edge piece of technology,

sonar imaging.

In 1973,

oceanographer Paul Kronfield

was brought on to Marinatos' team.

He is tasked with scanning the seafloor.

He remembers his time with Marinatos well.

Professor Marinatos was very excited about Helike.

He said 'cause it's a undisturbed, classical city

that's basically been buried under the ocean

and undisturbed

for thousands of years.

With all the artefacts totally undisturbed.

For this grand expedition, no expense was spared.

Marinatos commandeered a Greek Navy landing craft

and outfitted it with a drilling rig.

If the sonar scanners identified any structures,

the team would drill an exploratory core sample

to see if they held any ancient remains.

The drilling ship was anchored offshore.

And it would come in out of the mist

and drop the ramp on the beach.

And all the scientists and engineers

would come charging down the ramp

like invading the beaches of Normandy or something,

except we were invading our local tavernas, for lunch.

At that time of year,

the night-blooming jasmine is booming,

and the fragrance is in the air,

and we'd be sitting there listening to Greek music

looking up at the stars.

"You know this is exactly how this was 2,000 years ago

"when the people of ancient Helike were having their dinner."

And it was a very magic time.

Back at sea, Marinatos's team scan the seafloor

hunting for any anomalies

or signs of structures.

It's like looking for a needle in a haystack.

But incredibly, they identified something.

We picked up pockmarks on the seafloor.

And they were very intriguing, in straight lines.

God generally doesn't draw straight lines.

So, this could mean it might be man made.

It could be a road

or, it could be a wall,

we didn't know.

With the possibility of ancient Helike

lying in the depths beneath their ship,

the team deployed the drilling rig

to retrieve core sample.

Had they finally found the lost city?

There was so much excitement each time we retrieved the core.

You know, sleep was impossible,

we had to be there

'cause everyone expected

to see some artefacts or something in there,

that would indicate a discovery.

It just kept everybody very much electrified.

But all they found was mud and gravel.

After having spent all that time drilling

and sub-bottomprofiling,

and then to find nothing,

it was very disappointing.

Despite working through the night for days on end,

there was absolutely no sign of Helike.

And with the excavating season ended,

another chapter in the hunt for Helike came to a close.

For Spyridon Marinatos,

he would never get the chance to search again.

The following year, in 1974,

he died of a stroke while excavating on Santorini.

He is buried at the site.

The location of the lost city of Helike

remained a mystery, for now.

Archaeologist Professor Dora Katsonopoulou

grew up on the shores of the Corinthian Gulf,

close to where Helike was said to be located.

She is well acquainted with the legend

of the ancient city's destruction.

People who were raised in the region,

they all hear about this story

because Helike was the most

important city in the region.

When I was a child,

I was always dreaming of becoming an archaeologist someday,

in order to try and find this famous lost site.

So it was a childhood dream, I would say.

In 1988, Katsonopoulou assembles a team

and begins turning her dream into a reality.

She picks up where Marinatos left off,

using sonar scanners

to map the bottom of the Gulf of Corinth.

Soon, the sonar picks up something intriguing.

In one location,

we found remains of something

that looks like been man made.

It's something that has to do

with installations of a port.

And in another location, in a greater depth,

we may have remains of some wrecks of ships.

Analysing the sonar read out

was a man now familiar with the region,

oceanographer Paul Kronfield.

We saw ten of these features,

ten parabolic type features

under the sea Paul Kronfield bed.

It was very exciting.

According to Aelian, the Roman writer,

the night that Helike was destroyed,

there were ten Spartan ships

at anchor in Helike's port.

For Katsonopoulou,

it was starting to look like

they'd uncovered an ancient port.

If they could identify the ten shapes

shown on the sonar scans

as the ten sunken Spartan warships

told in the Helike legend,

then surely they'd have finally located the lost city?

But sonar scans alone aren't proof.

To be sure the team needs to dive

and examine the structures.

But here, they run into a problem.

The Corinthian Gulf, particularly in this area,

is very muddy.

And when divers go down,

as soon as they move toward the target,

it's, you know, a real cloud of mud

that is raised in front of them,

so they cannot really see.

It's a very difficult sea to explore.

The muddy conditions on the sea bed

make it impossible to identify these structures for certain.

Still, Katsonopoulou has a hunch

these underwater features represent the ancient port of Helike.

But how to be sure?

She needs a way of narrowing down the search area.

Were there any clues that located Helike

near these sonar hits?

Katsonopoulou returns to the ancient texts.

Reading the work of the ancient Greek geographer Pausanius,

she comes across something -

a description of Helike

in relation to the neighbouring town, Aigion.

Crucially, it mentions the distance.

One says that Helike is 40 stades,

that is 7km,

east of the city of Aigion.

Going further east,

he also comes to another monument

in the area, which is known as

the Cave of Heracles Vouraikos.

And he gives us a distance of Helike

from the cave of about 5.5km.

It's said that the people of Helike came there

to leave offerings to the demigod Heracles.

The location of the cave is still known today.

It's a key clue for Professor Katsonopoulou.

If Helike is within 7km of the town of Aigion,

and 5.5km of the Cave of Heracles,

then the lost city must lie in the area

where these measurements cross over.

The port features that Katsonopoulou uncovered

are well within this region.

They match the location of the ancient geographical texts.

But despite repeated sonar scanning,

all they could find

was evidence of a port.

Why wasn't the rest of the city visible on the sonar scans?

Katsonopoulou looks again

to the ancient descriptions of Helike's destruction.

These texts have been studied again and again

by archaeologists before her.

But Katsonopoulou has an advantage,

she can read these works in ancient Greek,

as they were written.

Had any clues been lost in translation?

As she pores over the ancient writings of Strabo,

she realises incredibly this might be the case.

It all hinged on the meaning of the word, 'poros',

the body of water

that Helike was said to have been submerged in.

Poros, in ancient Greek,

means a narrow passage of water.

But most archaeologists

had interpreted this as the Corinthian Gulf.

Which was absolutely wrong,

because the ancient sources

knew the Corinthian Gulf by name.

So they could mention the Corinthian Gulf,

they didn't have a reason to say, 'poros'.

Now what poros would mean

in my interpretation

was an inland lagoon or lake.

According to Professor Katsonopoulou's research,

the lost city of Helike

wasn't at the bottom of the Gulf of Corinth after all,

but had been submerged in an inland lagoon.

It's a blow for those hoping Helike is Atlantis.

Plato's mythological city

had been submerged and lost to the seafloor,

not a lagoon.

But still, in the search for Helike,

it's an incredible breakthrough.

It was beginning to make sense

why Katsanopoulou's sonar scans only showed a port,

not the rest of the city.

There was only one problem,

if you're thinking about this as a lagoon,

there isn't a lagoon there now,

there's just solid land.

So, where was the poros?

OK. Then I thought,

"Since we have a poros,

"that is an inland lagoon,

"then the ruins of the city

"should lie under this lagoon,

"because this lagoon

"covered up

"actually the destroyed city."

But at the point where

the sonar scans had identified a port,

there was no lagoon, only dry land.

But all of Katsonopoulou's evidence pointed to Helike being here.

Was it possible that the lagoon had dried up?

The fact that you have a feature

close to the shore that may belong to a port,

that shows to you that the city is on land.

So we said,

"OK, we checked it out, it's nothing in the sea,

"we have now to prepare

"for starting on land."

Katsonopoulou steps ashore.

Was there any evidence that this area had once been underwater?

If she could find any,

then she would be one step closer

to locating the lost city of Helike.

Among the trees on a farm,

just outside the town of Rizomylos,

Katsonopoulou notices something unusual -

a bridge but no river.

Examining the geology of the surrounding area,

it becomes clear this bridge wasn't always over dry land.

Over millions of years,

the craggy mountains further inland

have been eaten away by rivers coursing through them.

As the rivers make their way to the coast,

they carry with them the huge amount of rocks and debris.

One of the things that really impressed me

was the sheer amount of material

that was coming from the mountain side.

Those rivers that were coming through

were bringing huge amounts of debris down

and spreading it across the coastline.

So this was one of the most dynamic landscapes

I'd ever encountered.

Each winter,

the rivers break their banks

and deposit sediment across the entire plain.

It explains why the bridge is now over dry land.

That bridge was at one point over a river.

And it's no longer over a river,

the river's about 500m away.

So that tells us that the rivers

have changed since the classical time.

As the sediment builds year after year,

the rivers gradually become silted up

and the water changes course.

The bridge is a feature

that has to do

with the geomorphological changes of the plain.

Actually the bridge is evidence

for the shift of the river.

For Katsonopoulou, it's a profound realisation.

The lost city of Helike was submerged in a lagoon.

But all her evidence pointed to the location being on dry land.

Katsonopoulous suspects

a lagoon was once here,

but had silted up over time.

The lagoon had completely been silted

over by the sediments brought down by the rivers.

And that's why today you do not see any lagoon in the area.

The lagoon, of course, it is buried under the dry land today.

The ancient texts, the sonar scans,

the existence of a lagoon,

all pointed to Helike being under this plain.

But to know for certain,

her team will need to break ground.

Katsonopoulou and her team

conduct a series of extensive surface surveys

along the coastal plain.

They drill boreholes down to a depth of 15m

and examine the samples

for any signs of ancient life.

In 1993, they find some.

Pieces of pottery.

Inside these soils samples

were found the first pottery fragments.

Until then,

nothing was known from this area.

Even to find some first

small pottery fragments,

it was something to rejoice at.

For Katsonopoulou,

these finds indicated an ancient settlement

that's likely to exist beneath their feet.

Could these be the ruins of Helike?

The team prepares to excavate.

But before the archaeologists can start,

they are woken in the night

by a horrific noise.

We were conducting our first excavation in the area

when this earthquake happened,

the Aigion earthquake of 1995.

We were very much alarmed because, you know,

that happened early in the morning.

Of course living through

an earthquake event,

it's something dramatic

and terrifying.

When the dust from the earthquake settles,

Katsonopoulou's team finally break ground.

Here they uncover the remains of an ancient building.

Helike was destroyed in 373 BCE,

during the Classical Period.

But frustratingly, the remains uncovered are Roman.

They date from a far later period in history.

But for Katsonopoulou, it proves they're on the right track.

For me, it was very important.

Because that proved for good

that there is ancient occupation in this plain.

And you have the real evidence in front of your eyes.

You have a building.

As more excavations are conducted,

it becomes clear that the site held a very long occupation history.

It's promising news.

But to edge closer to proving this is Helike,

Katsonopoulou's team

need to uncover evidence

that this site was inhabited

during the Classical Period.

In the foundation trench of this building,

we discovered a nice group

of pottery fragments from earlier periods,

like Classical and even earlier,

going back to the 8th century BC.

That showed to us that we were in the right track,

we were in the right area.

The wealth of finds uncovered indicate that a significant,

prosperous, ancient city once existed here.

But although the team have found traces

of settlements from the Roman,

the early Bronze Age and Helladic periods,

they haven't found any structures

from the Classical Period,

the era that Helike existed in.

Until Professor Katsonopoulou's team make a discovery in 2001.

Beneath an olive grove,

they uncover a series

of structures teaming with artefacts.

When they date them,

it becomes clear they've hit the jackpot.

We can date these buildings as Classical

because of the finds

that is pottery, coins and other,

that date to the 4th century BC.

The artefacts fit the time frame

for the story of Helike's destruction.

And as Katsonopoulou sifts through the remains,

she comes across a timely remainder

that people once lived here,

an object which appears to be a family heirloom.

One of the more special finds

is the terracotta painted head of female idol,

which actually chronologically is not Classical,

is earlier than Classical.

Because this is a 6th century BC find,

and obviously this belonged

to the people who own this building.

And this was something like

they had inherited

from one generation to the other,

and was still remaining in this building in 373 BC.

Finally, Professor Katsonopoulou has proof

that a large city existed here in 373 BCE,

the year that Helike is said

to have been destroyed by a tsunami.

Had Katsonopoulou finally uncovered the lost city?

The ancient ruins her team have uncovered

match the historical

and geographical descriptions perfectly.

But a key question remains unanswered -

was there any proof

that this site had been destroyed

by a tsunami and submerged in a lagoon?

Without this, it's impossible to know for certain

whether the lost city of Helike

had finally been found.

If these ruins had once lay underwater,

then the remains of aquatic life might still be present.

Katsonopoulou's team re-examine the soil

brought up by bore hole drillings across the region.

When they analyse the sediment samples,

they make an important discovery,

evidence of microscopic organisms

usually found in a marine environment.

You have organisms in this soil sample

that show that the environment

in which they are found

is definitely a lagoonal environment.

These ruins were once submerged in a lagoon,

just as the ancient accounts

of the destruction of Helike described.

For Katsonopoulou,

she has proof that these ruins

are the lost city of Helike.

It's an incredible moment.

Finding something that,

for over a century,

was an unresolved problem for archaeology,

was a major moment.

It's an amazing feeling,

that it is difficult to describe.

It is a life's work for me.

Could these ruins finally reveal the truth

behind one of the Ancient World's greatest mysteries,

what actually caused the destruction of Helike.

According to the ancient texts,

Poseidon was angry with the inhabitants of Helike

and caused an earthquake,

which triggered a tsunami

that overwhelmed and submerged the city.

But was a tsunami actually responsible

for the eradication of Helike?

As Katsonopoulou's team examined the ruins,

they found clear evidence

that the structures had been destroyed,

and crucially, the destruction pattern

pointed to a great wave.

In two different locations

have been found Classical remains

of buildings destroyed,

and the interesting thing

is that in one case,

the way one of the walls is fallen,

shows that it was perhaps

the result of a backwash of a tsunami.

It was looking like the ancient texts were correct.

A tsunami had engulfed Helike.

But a closer analysis of the destruction layers

shows something else,

Helike had suffered wide scale destruction

before the tsunami hit,

almost as if the city was swallowed by the ground

prior to being engulfed.

What could have caused this?

The Gulf of Corinth is a really interesting area,

because it's the most seismically active part of Greece,

and Greece is the most seismically active part of Europe.

Geologist Iain Stewart

was investigating another earthquake

that had occurred in 1861

when his path crossed with Katsonopoulou.

What he discovered offered an answer.

I was doing what was called paleoseismology.

So, you kind of excavate along the fault line,

and you get some evidence

of when that fault last moved

during an earthquake.

I knew there was an earthquake that had happened in December 1861,

so my question was, was the fault that I was looking at

the one that also moved

in the earlier earthquake of 373 BC?

Stewart's geological analysis

highlighted many similarities

between the earthquake of 1861

and the earthquake that triggered the tsunami of 373 BCE.

His findings match the destruction seen at Helike.

There was large scale coastal submergence,

large areas of flooding,

there was lots of mud and water

that had erupted out.

There was fissuring of the landscape.

373 BC was a really big earthquake.

The plain dropped, maybe 3m.

The tops of the olive trees

were just sticking out of the water.

This would have been the most intense jolt

of this whole landscape.

The whole area would have been shaking.

And then, you just get the feeling of it

kind of collapsing down

into the sea.

It would have been

the most extraordinary event to have lived through.

Terrifying.

For Stewart, it seemed likely

the earthquake of 373 BCE

didn't just cause a tsunami,

but shook the ground so violently

that Helike was engulfed by water from below.

It's a process known as liquefaction.

It occurs when wet, loosely packed soil

is shaken by an earthquake.

It causes the soil particles to break contact

and the moisture rises to the surface.

Solid ground takes on the consistency of a liquid.

The main effects of liquefaction in 373 BC

are dramatic outpourings of water,

in some case kind of bursting and flooding out,

but in some cases fountains.

Like, almost like volcanic eruptions,

exploding out under great pressure.

Changing, transforming the whole

physical kind of landscape,

burying buildings,

burying people perhaps.

It seems that in 373 BCE,

the ancient city of Helike

was hit by a cataclysmic earthquake.

As the earth opened up,

the city and its inhabitants

were flooded by water bursting up from beneath their feet.

With the city all but destroyed,

the tsunami triggered by the earthquake

engulfed all that remained of Helike.

The city was lost beneath the waves.

While Helike is giving up its secrets,

the myth of the lost city of Atlantis

remains as big a mystery as it's ever been.

But as archaeologists continue to examine the evidence at Helike,

similarities between the city's demise

and Plato's tale of Atlantis become clear.

Could Helike's destruction be its inspiration?

Poseidon was the patron

and most important god of Helike.

As god of Earthquakes,

Poseidon was the most important god for Atlantis.

But there is another reason

that Plato would be interested in Helike's destruction,

he was in Athens,

Helike was not very far from Athens.

The phenomenon that destroyed Helike

impressed very much the ancients,

so Plato heard about it,

there is no doubt that he heard

and he knew about it.

In Plato's tale,

the citizens of Atlantis angered the gods,

who then sent an earthquake

that made Atlantis sink into the sea.

The Helike legend offers up a direct parallel.

Poseidon is said to have destroyed the city

in a fit of wrath

with the way the people of Helike

had behaved towards some visitors

wishing to venerate him.

If you look at the period in Greek history

that Plato lived through,

is there were lots of big earthquakes.

Ones like Helike, where you had cities destroyed overnight.

So to my mind,

it's perfectly reasonable

what Plato did was he took reality

that he was seeing unfolding around him,

and he transposed that into a story of a civilisation

that happened way in the past.

So it's one of those factional accounts really,

where there's a bit of fact in there

but there's also a little bit of fiction.