All language subtitles for Drain the Oceans Series 1 Lost Worlds of the Mediterranean 720p

NARRATOR:
Beneath the clear blue waters

of the Mediterranean lie
treasures of ancient empires,

relics of their bloody wars,

and secrets of the seismic
forces that shaped them,

lost beneath the waves...

until now.

Imagine if we could
empty the oceans,

letting the water drain away

to reveal the secrets
of the seafloor.

Now, we can.

Using the latest underwater
scanning technology,

piercing the deep oceans,

and turning accurate data
into 3D images.

This time,
what apocalyptic disaster

triggered the collapse
of Europe's first civilization?

Can an extraordinary
2,500-year-old shipwreck

unlock the secrets
of Ancient Greece?

How did these deadly objects

turn Ancient Rome
into a superpower?

And why does the Sin City
of the Roman Empire

lie abandoned
beneath the waves?

(music)

(music)

(music)

Ancient people call it
the Middle Sea,

the center of the known world.

The Egyptians,
Greeks and Romans

build mighty civilizations
upon its shores.

Empires battle for supremacy
across its waters.

Cities grow rich and powerful
through trade.

The Mediterranean becomes
a superhighway,

connecting cultures that
will shape the modern world.

But only by draining the sea
can we reveal

its biggest and most
terrifying secret.

What happened on this
spectacular Greek island

to doom an entire civilization?

COSTAS SYNOLAKIS: They must have
thought this was it,

the end of the world.

NARRATOR: 3,600 years ago.

15 centuries before
the Roman Empire.

A mysterious people dominate
the Mediterranean.

We call them the Minoans.

Their home is on Crete.

Here they build magnificent
temples and palaces,

and decorate them
with stunning frescoes.

Celebrating their love
of life and of nature.

But there's a darker side, too.

The Minoan royal palace
at Knossos

is said to contain a labyrinth.

Home to the Minotaur.

A fearsome creature...

part man, part bull,

with a terrible appetite
for human flesh.

But apart from a grisly myth,

much about the Minoan world
still remains a mystery.

MICHAEL SCOTT: We can't
decipher their language.

We only have their
archaeological remains,

but what that tells us, I think,

is that they were
extremely imaginative,

they were extremely adventurous,

and that they developed

a sophisticated
hierarchical society

that was capable of producing
elements of art and architecture

which still astound us today.

NARRATOR: Historians do know
that the Minoans spread

across the Mediterranean,

trading olive oil and pottery
for gold and ivory,

growing ever richer
and more powerful.

And then,
in the 15th century BC,

their ancient civilization
begins to fade

from the pages of history.

For centuries,
no one knows why.

Until scientists start
to look closely

at the nearby island
of Santorini.

SYNOLAKIS: Santorini, it has
this very, very calm water.

It's almost like it plays
with you and deceives you.

Looking at this view,
you would never imagine

how dangerous it once was
and how dangerous it is.

NARRATOR: The island is famous

for its spectacular,
jagged cliffs,

which tower above
a beautiful natural harbor.

But what created them?

And can they help explain
the downfall of the Minoans?

Marine geologist Evi Nomikou
believes that crucial clues

may lie deep beneath
Santorini's tranquil waters.

EVI NOMIKOU:
As I was born in Santorini,

I wanted to study the area
to reveal their secret.

Being a marine geologist means
that you're having access

to the mystic world
of the seafloor,

so you can see features
that nobody else can see.

NARRATOR:
She harnesses the latest

multi-beam sonar technology

to scan the depths
of the huge bay.

By transforming her data
into powerful computer imagery,

it's possible to drain away the
waters of the Mediterranean...

(music)

...and reveal Santorini's
terrifying secret.

The sheer cliffs tower
1,000 feet above sea level

and drop a further 1,000 feet
to the seafloor.

Framing a vast basin

large enough to hold
10,000 Olympic stadiums.

The basin is a huge crater,

and Santorini itself is the
remnant of a gigantic volcano.

(music)

But that's not all.

On the rim of the crater,

more evidence of Santorini's
violent past.

(music)

(screams)

Undiscovered until 1967,

these shattered ruins
are all that remain

of a once-thriving city,

known today as Akrotiri.

It was destroyed when
the volcano erupted,

and buried under so much ash
that it remained hidden

for 3,500 years.

LEFTERIS ZORZOS: It's almost
like a window back in time,

where you can see how it was
when it was destroyed.

NARRATOR: And deep in the ruins

archaeologists discover
something remarkable.

(rumbling)

These stone steps
were not broken

by the ash and lava
from a volcano.

(rumbling)

They were shattered
by an earthquake.

ZORZOS: When the earthquake
happened,

everyone fled their town,

but then they came back to start
rebuilding their homes,

and this is exactly
what we're seeing here.

NARRATOR: Believing
the danger over,

people move furniture
into the streets,

so they can start repairing
their houses.

ZORZOS: We're seeing the beds
placed outside of their homes,

we're seeing the stones and mud

getting ready to be used
to rebuild these homes.

NARRATOR: But then they are
struck by an apocalypse.

(rumbling)

(explosion)

The first stage of the eruption
is so powerful

that it engulfs Akrotiri

and suffocates the whole island
in a thick layer of debris.

And the date of this
cataclysmic eruption?

Around 1625 BC, the same time
as the Minoans

begin to disappear from
the pages of history.

But how could a single eruption
trigger the collapse

of a great civilization based
on an island 70 miles away?

Until recently most scientists
have focused

only on the evidence
above ground.

But Evi Nomikou believes
that once again

the real clues lie underwater.

EVI NOMIKOU: Scientists
have been occupied

studying only
the on-land geology,

so we are starting
mapping the seafloor,

in order to find out
the total volume

of that big, destructive
eruption.

NARRATOR: Evi heads outside
the great crater

to hunt for new evidence
on the seabed.

And what she finds
is extraordinary.

Proof of the sheer scale
of this eruption.

As the waters of
the Mediterranean recede

still further, they reveal
wide stone terraces,

fanning out from
the mouth of the volcano...

the size of 20-story buildings.

They point to one cause.

They're called
pyroclastic flows:

torrents of superheated gas
and molten rock.

NOMIKOU: The pyroclastic flow
can cover everything.

They travel like a hurricane.

They can destroy
everything on their path

because of the high temperature,
up to 1,000 Celsius.

NARRATOR:
When they hit the sea,

the pyroclastic flows cool and
become solid ramparts of rock.

Around Santorini, they stretch
for a staggering 20 miles

in every direction.

Evidence of multiple eruptions
lasting for days.

By measuring
the stone terraces,

scientists calculate that
the volcano throws out

14 cubic miles of debris.

An eruption far more powerful
than they had ever imagined.

It's one of the biggest
volcanic explosions

in the history of the planet.

(explosion)

SYNOLAKIS: Let's try to imagine
what this eruption looked like.

If you were sitting somewhere in
any of the neighboring islands,

it would have appeared
like the end of the world.

NARRATOR: At first
the volcano blasts out

a column of superheated debris
more than 20 miles high.

SYNOLAKIS: This huge funnel
of black ash and cloud

could have been seen going
all the way to the sky.

NARRATOR: Some of the volcanic
plume falls to Earth

many miles from Santorini.

SYNOLAKIS: It would have been
raining pumice

on the surrounding islands.

NARRATOR: But now
the volcano unleashes

its most devastating surprise,

and in its path lies Crete,
the center of the Minoan world.

NARRATOR: 70 miles
from Santorini,

the Minoans on Crete see the
soaring column of ash and smoke

from the erupting volcano.

But they have no idea
of the disaster to come.

The volcano blasts millions
of tons of lava into the sea.

Triggering wave after wave
of powerful tsunamis.

SYNOLAKIS: When the tsunami
arrived in Crete,

they were probably taken
totally by surprise.

Imagine seeing
this wall of water,

in some places ten meters high,
advancing in.

It must have looked like
this was the end of the world.

Totally unexpected.

The wrath of the gods.

NARRATOR: Entire coastal
communities are swept away

by waves up to 30 feet tall.

Ports are destroyed
and ships smashed to pieces.

And the gods
aren't finished yet.

After the eruption
and the tsunamis,

another disaster is looming.

Clouds of volcanic ash
cast a deadly pall

over the whole Mediterranean,
dramatically cooling the Earth.

SCOTT: There were a series
of effects from the eruption

that together fatally weakened
the Minoan civilization.

A tsunami event, a divine event.

The destabilization
of their economy,

the failure of harvests
over several years.

That was the moment when Minoan
civilization started to die.

NARRATOR: Without their ports
and ships,

the Minoans lose their mastery
over the Mediterranean.

Invaders challenge their power.

And as the sun sets on the
collapsing Minoan civilization,

new powers arise.

500 miles from Crete,
just off the coast of Cyprus,

the draining waters
of the Mediterranean

reveal a remarkable discovery
almost 2,500 years old.

What can it tell us about
the lives, the power,

and the pleasures
of the Ancient Greeks?

In the centuries after
the fall of the Minoans,

the city-states of Greece

produce dazzling art
and architecture.

Forging ideas in mathematics,
democracy and theater

that still shape our world.

The Greeks take to the sea
in their wooden sailing ships

risking their lives
to explore, colonize,

and trade with each other.

Hundreds of boats shuttle
across the Mediterranean,

linking settlements in
Africa, Asia and Europe.

They are the lifeblood
of Greek civilization.

But these ships are a mystery.

Only a few remnants have
survived to offer a glimpse

into how they worked
and what they carried...

until now.

A shipwreck,
recently discovered

in the seas off Cyprus,

is helping to bring this
lost world back to life.

Archaeologist Stella Demesticha
and her team

are unlocking
the wreck's secrets.

Where did it come from?

What was it carrying?

And why did it sink?

STELLA DEMESTICHA: It's pretty
deep, so it takes a while

when you're diving before
you can see the sea bottom.

SCOTT: It looks all very
higgledy-piggledy,

it looks like, well, someone's
dropped a whole load of garbage

in the ocean.

NARRATOR: But this apparent
chaos is packed with clues

about the lost world
of the Ancient Greeks.

DEMESTICHA: This is really
fantastic for an archaeologist.

NARRATOR: Exploring such
a deep and complex site

is challenging.

DEMESTICHA: Diving at 45 meters
has several constraints,

and time is one of them.

The maximum we can stay per day
is 20 minutes.

NARRATOR: It's almost
impossible to work effectively

at such depths.

So the team explores the site

using a technique
called photogrammetry,

taking hundreds of pictures
of the wreck

from different angles.

DEMESTICHA: So instead of trying
to make decisions at 45 meters

where your brain
doesn't work properly,

taking the pictures allows us
to have the luxury

of diving through the screen
of our computer

as long as we wanted.

NARRATOR: Using the unique
photogrammetry data,

it's possible
for the first time

to drain the Mediterranean...

allowing sunshine to illuminate
a site that's been in darkness

for 2,500 years.

(music)

The debris lies
in the shape of a ship.

Much of the timber hull
has rotted away,

leaving only its ancient cargo.

Hundreds of earthenware jars,
known as amphorae,

piled neatly on top
of each other,

many of them still intact.

(music)

SCOTT: Amphorae look very odd.

They look very ungainly
and not very well designed

to be storage jars or certainly
container jars on a sea vessel.

But they are a design that's
evolved over centuries.

And actually if you stack them
all really neatly together,

they do all make sense,

and they were the way
that you transported things

around the ancient world.

NARRATOR: Amphorae like this

give the archaeologists
some vital clues.

Their distinctive shape varies,

depending on where and when
they were made.

This one dates from
the 4th century BC

and comes from
the Greek island of Chios,

500 miles from the wreck site.

So what was in it?

Although the amphorae
are all now empty,

they offer intriguing clues
about what they once contained.

DEMESTICHA: In this case we have
the opportunity to see evidence.

This dark coating
inside the amphora,

we have to imagine that it was
all over the inside walls,

and it was pitch, or resin,

so it was a kind of sealant
to make these walls waterproof.

So we are sure that these
are Chian wine containers.

NARRATOR: Wine from the island
of Chios is highly prized

throughout
the Ancient Mediterranean.

The wrecked ship is loaded
with the equivalent

of more than 10,000
modern-sized bottles.

A hugely valuable cargo
and a telling insight

into the Ancient Greek trade
in luxury goods.

SCOTT: The Greeks
loved their wine.

This little wreck off Cyprus

is the tip of the iceberg
of the wine trade.

It was an absolutely fundamental
part of their society

and of all their
cultural experiences,

whether that be religious

or whether it be
letting their hair down

and having a really good time.

DEMESTICHA: The greatest thing
about Ancient Greeks

is their love for life.

They like to talk, to think,
to discuss, to drink, to party.

SCOTT: There was a great profit
to be made

in making sure that the rich
around the Mediterranean world

had a good supply of
very good wine to drink.

NARRATOR: Trading in wine
and other luxury items

makes good money for
the Greek city-states.

But their ships carry
an even more precious cargo,

as they traverse
the Mediterranean and beyond,

from Egypt to Southern France,

they spread Greek
ideas and culture

that influence
Western civilization

to the present day.

But this cargo never
reaches its destination.

DEMESTICHA: One of the most
important questions that we ask

in shipwreck archaeology
is why this ship sunk.

NARRATOR: The biggest clue is
the shape of the debris.

The way that the jars
lie grouped together

rather than scattered about

proves that the vessel
didn't capsize.

So what did happen?

DEMESTICHA: The ships in
antiquity were open-decked.

The hold was not covered
with a deck,

so when the waves were
very high, or we have a storm,

then the water was coming in.

NARRATOR: The ship is most
likely overwhelmed by a wave.

Pulled down by the weight
of all the expensive wine

to a watery grave.

(music)

(music)

(music)

As the waters
of the Mediterranean

continue to drain away,

they uncover unique evidence
of a titanic clash

between two ancient
superpowers.

This is the site of a battle

that would change
the course of history.

WILLIAM M. MURRAY: When they saw
the Romans in front of them,

they had one of these
'Oh, no!' moments.

NARRATOR: What can these
bizarre objects on the seabed

tell us about the merciless
rise of the Romans?

NARRATOR: The third century BC.

Rome already controls
mainland Italy,

and has ambitions to expand
across the whole Mediterranean.

But its navy is weak.

JON HENDERSON: Rome was known
as being a terrestrial power,

not a maritime power, it was not
known for fighting sea battles,

but they were set on
a militaristic path

of maritime control.

NARRATOR: This brings them
into conflict

with another superpower
of the Mediterranean:

the Carthaginians.

SCOTT: The Carthaginians were
great traders, great seafarers,

controlling most of the west
and central Mediterranean,

and it was that fact

that brought them
into conflict with Rome.

NARRATOR: Carthage,
from its position

on the north coast of Africa,

commands the most powerful navy
in the region.

To challenge Carthage,

Rome must first learn
a new kind of naval warfare.

So begins a titanic struggle

that will last for
more than 100 years.

The winner will dominate
the Mediterranean

for the next seven centuries.

Its first truly decisive
encounter happens

somewhere off
the west coast of Sicily,

near the Egadi Islands.

Here, according to
ancient historian Polybius,

the mighty navies
of Rome and Carthage

go head-to-head
in an epic battle.

He describes the clash
of two huge fleets

involving 400 ships,
and at least 100,000 men...

turning the waters of
the Mediterranean blood-red.

But Polybius writes his history

at least half a century
after the battle

and for a Roman audience.

So how reliable is his account?

However huge this battle
may have been,

no one has ever been able
to find any trace of it.

MURRAY: Taking the description
from an ancient historian

and actually pointing
to the exact place

on the surface of the globe
where the battle took place

is extremely difficult.

NARRATOR: Bill Murray and
a team of marine archaeologists

are on the trail of
some extraordinary finds

reported by local fishermen.

But the area they need
to survey is huge,

many miles across.

So first, they sonar scan
the seabed.

Then they launch
a remotely operated vehicle

to investigate the finds.

(music)

(music)

PETER CAMPBELL: As you're
watching the live feed

of the video from the ROV, and
it's going across the seafloor,

the shapes suddenly
pop into view,

and it's incredibly distinctive.

So there's a great moment
of excitement

as these objects are first seen.

NARRATOR: They discover
a truly astonishing shape

300 feet down.

CAMPBELL: These are
the rarest artifacts

we have from antiquity.

NARRATOR: So what is it?

Using the data gathered
by the expedition,

it's possible to pull the plug
on the Mediterranean,

emptying the waters from
around the coast of Sicily.

The mysterious object on the
seabed comes clearly into view.

It's three feet wide
and made of metal.

Its jagged edges suggest
a deadly purpose.

SCOTT: So these are
bronze battering rams.

They would have been attached
to the front of a ship,

and this was the main method

of attacking and destroying
ships in antiquity.

NARRATOR: Rams are
the superweapons

of ancient naval warfare.

The large vertical fin is
like a splitting axe,

and the horizontal fins
are like blades,

to slice through
an enemy ship's timbers.

SCOTT: You didn't
have cannon fire,

there were no kind of guns
a la Pirates of the Caribbean

or anything like that.

The only way to take down
the enemy ship

was to smash a massive hole
in the middle of it

and let it sink to the bottom,

and the only way of doing that
was to ram it.

(crashing)

NARRATOR: A closer look reveals

that this ram is
battle-damaged,

its metal edges
broken and distorted

by a violent collision.

MURRAY: In one episode

we're told that the men
up in a forward tower

were literally catapulted
out of the tower

and into the sea
after a ram strike.

And we're told that it was
an effective ram strike,

because as the ancient author
wrote, 'Bronze hit bronze.'

NARRATOR: And this isn't
the only discovery.

Based on data from the survey,

draining away more
of the Mediterranean

reveals a remarkable pattern.

Ten more rams, scattered

across two square miles.

More than enough
to convince historians

that an important naval battle
took place here.

But is it the legendary
Battle of the Egadi Islands

described by Polybius?

An unlikely piece of evidence
may hold the answer.

A single amphora storage jar,
found near one of the rams.

By analyzing its shape

archaeologists can narrow down
when and where it was made.

It's like finding
a black box recorder.

The team believes the amphora
is Carthaginian

and dates
to the 3rd century BC,

the same period as the Battle
of the Egadi Islands.

The historian Polybius
describes how the Carthaginians

are carrying supplies for
their soldiers in Sicily.

Could this amphora
be part of that cargo?

POLYBIUS: The plan was to cross
to Mount Erice,

unobserved by the enemy,
and offload the stores.

Then take on soldiers
in the lightened ships

and engage the enemy.

NARRATOR: But the Carthaginians
never make it.

Compelling evidence
from the drained seabed

now indicates this is
where it all happened.

MURRAY: A number of rams line up
and give us a bearing

that makes some sense,

and that's fascinating,
that is exciting.

NARRATOR: The words
of an ancient historian

and the evidence
of modern technology

both point
to the same conclusion:

this is the site of the Battle
of the Egadi Islands.

MURRAY: It was an important
enough event for the Romans

that they remembered the date.

It was actually written down
in a calendar somewhere,

and we know that it occurred
on 10 March, 241 BC.

This is not your typical naval
battle where both sides prepare.

This was a battle
of opportunity.

NARRATOR: The Carthaginians,
still laden with supplies,

head for shore believing
the coast is clear.

But the Romans keep dozens
of their ships hidden

behind one of the islands.

It's a huge ambush.

MURRAY: The lookouts spied the
Carthaginian ships coming in,

and as the Carthaginians saw
the Romans in front of them,

they had one of these
'Oh, no!' moments.

CAMPBELL: So we're talking about
tens of thousands of men

on board these ships,

and they would have lined up
across from each other

in lines of battle,

headed toward each other
at a great rate,

and smashed into each other
head-to-head.

(crashing)

(men yelling)

NARRATOR: Polybius describes
what happened next.

POLYBIUS: Before long,
they were defeated.

50 of the Carthaginians' ships
were sunk,

and 70 captured
with their crews,

while the prisoners
numbered almost 10,000.

NARRATOR: Another discovery on
the seabed is a stark reminder

that this epic victory came
at a high price in human life.

This is the last resting place
of thousands of brave men.

And it has been judged
so important

that its exact location
must remain secret.

CAMPBELL: There's nothing else
really like this.

It's the first
ancient battle site

that's ever been discovered.

It's just an incredible
debris field.

SCOTT: The Battle of the Egadi
Islands was the turning point,

when a Roman fleet managed
to absolutely trounce

a Carthaginian fleet at sea.

CAMPBELL: This was
the defining battle

where Rome went from a regional
power to a superpower.

NARRATOR: The struggle between
Rome and Carthage

would last for another century.

But victory here
set Rome on a path

to shaping the destiny of
Europe for the next 700 years.

As the last of its water
runs away,

the Mediterranean reveals
a final secret.

What can draining
the Bay of Naples teach us

about the glory and the
decadence of the Roman Empire?

NARRATOR: 2,000 years ago

Rome has grown far beyond
its Italian homeland.

Its legions control a vast area

from North Africa
to Northern Europe,

from Spain to the Black Sea,

and the Roman navy dominates
the Mediterranean,

from its port next
to the city of Baiae

in the shadow
of mighty Vesuvius.

Baiae earns a reputation as
the Sin City of Ancient Rome.

It's famous for debauchery
and excess.

But what really went on
in this seaside party town?

And why does so much of it lie
abandoned beneath the waves?

Now, marine archaeologist
Jon Henderson is exploring

the secrets
of this sunken city.

Starting with
the huge harbor walls

that once surrounded
the city's port.

HENDERSON: These are built
by the Romans.

They were incredible engineers.

You can still see
the artificial construction

of this very clearly.

You can see the brickwork,
overlapping bricks.

Amazing!

NARRATOR: Beyond the port walls
lie magnificent villas

where Roman emperors
host lavish parties.

HENDERSON: Look at this.

This is a mosaic floor
of one of the bath houses.

Looks like it was
just done yesterday.

It's phenomenal!

Absolutely amazing!

This is called the nymphaeum.

It's actually
an elaborate dining room

for the Emperor Claudius.

You can imagine people
eating food

surrounded by
these water nymphs.

It was built to entertain the
emperor's most honored guests.

Well, one of the things
I'm interested in

is actually the scale
of the site.

Much of the focus has been on
the resort area of Baiae itself.

But on the margins of the site

there are constantly
new areas coming up.

(music)

That's it, slow it down.

There's a lot down there.

NARRATOR: So why did the Romans
lavish so much wealth

on building
a pleasure city here?

HENDERSON:
The Romans came to Baiae

because of the lovely maritime
climate and the thermal springs.

But Baiae was also
a very important port,

it's a natural port,

it's one of the best ports

on the western coast of Italy
at the time.

NARRATOR: Wealth brought
pleasure and excess

to this Las Vegas
of the Roman world.

HENDERSON: There were parties,
there was drinking,

it was a place
to get prostitutes,

and writers at the time referred
to it as 'a harbor of vice'

or 'a vortex of luxury.'

NARRATOR: The famous
Roman philosopher Seneca

is appalled by what he finds.

SENECA: Baiae is a place
to be avoided.

People wandering drunk
along the beach,

the riotous reveling
of sailing parties,

the lakes noisy with singing.

NARRATOR: But time is running
out for this party town.

Gradually many of its most
impressive public buildings

and private villas are
lost beneath the waves.

What happened?

Based on detailed
sonar scanning,

draining away the Mediterranean
begins to reveal the real story

of the rise and fall of Baiae.

It exposes just how much of
the city fell under the waves.

430 acres of streets, shops,

warehouses, and luxury villas.

Draining beyond the town
uncovers the reason--

an extraordinary landscape,

shaped by powerful
underground forces.

The whole town sits inside
the shallow crater

of a giant volcano.

HENDERSON:
You hear about Naples,

people talk about Vesuvius,
they don't seem to realize that

the whole western Bay of Naples
itself is a massive volcano.

We're actually standing
in a volcano now.

NARRATOR: The people of Baiae
may not understand

the unpredictable forces
stirring beneath them.

DOUGAL JERRAM: And we know
we're sat on a volcano.

But it's not
your normal volcano.

It's this much larger and much
more complex volcanic system.

NARRATOR: There's remarkable
evidence of its restless power

three miles away, across the
bay in the Temple of Serapis.

JERRAM: It's really when you
get into the Roman ruins

that you can see
what's going on.

You have to look closely,
though.

If you look up
at the column behind me,

you'll see in the middle part

it's got this strange
texture to it.

Lots and lots of holes in it.

There's even bits of shell
on this.

This is a stone-boring
marine mollusk.

That tells me that this stuff
has been under the sea.

Time enough for those mollusks

to get to grips
with the columns.

But look now,
these columns are in place,

and look where those
marker horizons are now.

That's like a tide
on the side of a bath

telling you where
the sea level was.

So we know that this has been
dropped under the sea,

and it's now risen above.

NARRATOR: Can draining
the waters of the bay

even further explain why
this ancient landscape

is constantly rising
and falling,

and finally show why the Romans
lost their Sin City?

NARRATOR: Baiae,
once a major Roman port,

lies half-submerged amid
a volcanic landscape.

(music)

Jon Henderson has been
exploring the area

beneath the waves,

and he finds a telltale sign
of the power at work here.

HENDERSON: So we've got
all these bubbles

are coming out of the ground,

all this hot air coming up
from the seabed.

You really get a sense here
of the power that's underneath,

waiting to burst out.

Hot water piling out
of the ground under the sea.

I've never seen
anything like this.

NARRATOR: These underwater
vents are superheated

by molten rock
from the volcano below,

evidence that the forces
stirring under Baiae

are highly active.

Locals call the area
Campi Flegri,

the Fields of Fire.

Now, for the first time,
draining the water

from the entire bay exposes
an extraordinary site.

24 separate volcanoes
nesting inside the crater.

It spans an incredible
38 square miles.

But geologists here
have been mapping

deep inside the Earth itself.

Now, draining not only
the Mediterranean,

but looking deep into
the layers of rock below it,

reveals a fantastical sight.

Giant cauldrons of
superheated molten rock,

known as a magma chambers,

that slowly empty and fill
over centuries.

Evidence that this
huge volcanic system

is still very much alive.

HENDERSON: Basically you've got
magma chambers

sitting under the sea, which
operate almost like bellows.

When they fill full of lava,
the ground goes up,

and then when they empty again
the ground goes down,

and this process is
going on constantly.

NARRATOR: It's as if the land
within the Campi Flegri crater

itself is breathing.

SCOTT: You feel like
you're standing

on some kind of giant's chest.

You feel minute compared
to the giant tectonic forces

that are creating
the world around you.

NARRATOR: The damage caused

by these breathing
chambers of magma

coincides with the decline
of the Roman Empire.

As part of the city slides
beneath the Mediterranean,

the population shrinks
and the parties end;

Sin City is no more.

Today, the scientists studying
the landscape here

believe that pressures
in the magma chambers

are increasing once again,

and that could have
catastrophic consequences

for the millions of people
living close by.

JERRAM: We know
it's an active system.

So one of the interesting
problems we have

with something the size
of Campi Flegri is,

is it going to erupt big or
is it going to erupt small?

NARRATOR:
Big could mean very big.

In AD 79,
nearby Vesuvius erupts.

It destroys
the city of Pompeii.

Thousands of people burn to
death or choke on volcanic ash.

But scientists know
the volcanic system

feeding the Fields of Fire
is far larger

and far more powerful
than Vesuvius.

And with so many people
living nearby,

it's vital to keep a close eye

on the breathing giant
beneath them.

JERRAM: It's even more critical

that we monitor
volcanoes like this,

and that's because we're verging

on the side of what we call
a supervolcano.

NARRATOR: Even the smallest
changes in the ground level,

or its temperature, could be
a vital warning sign

that the unstoppable forces of
nature are about to turn ugly.

JERRAM: If we had an eruption

where these multiple craters
evacuated,

it would be devastating.

It would essentially
flatten this area.

NARRATOR: The eruption could be
almost ten times more powerful

than the one at Santorini that
shattered the Minoan world.

(music)

Vast amounts
of volcanic material

would be ejected
into the atmosphere,

blocking out the sunlight.

Global temperatures
would plummet

with devastating consequences.

New scanning technology
reveals remarkable evidence

lying hidden beneath the waters
of the Mediterranean.

The raw forces of nature

still shaping
this volcanic landscape.

Priceless evidence of the trade
that drove the ancient world,

and an epic battle that changed
the course of history.