Original subtitles

NARRATOR: They're watching you.

More than 5,000 satellites circle the Earth.

Every day, they uncover new, mysterious phenomena

that defy explanation.

Revealed from space, Britain's secret terror factory.

BRADSHAW: It's a relic of death

and grief for millions of people.

NARRATOR: The temple of the eater of islands.

They skinned and de-boned their victims like livestock.

NARRATOR: And the land of the trillion-dollar druglords.

They make Pablo Escobar look like small fry.

NARRATOR: Baffling phenomena.

Mysteries from space.

What on Earth are they?

**

**

October 2017.

Eyes in the sky scan the Atlantic coast of

the county of Cornwall on the far southwestern tip of

Great Britain.

Passing over St. Ives Bay,

they capture something unexpected in the dunes below.

This is a super strange image.

It's kind of this lush green area,

but there's all kinds of weird geometric shapes protruding

from the landscape.

They're squares, there are lots of, like, indeterminate shapes.

And they're all kind of pockmarked

without much order at all.

This site is clearly on a pretty big scale,

but it's been abandoned.

So what happened here?

NARRATOR: Hooked by the image, archaeologist Rebecca Bradshaw

is heading into the dunes

to study the mystery shapes up close.

I'm not entirely sure why they would be here,

but because these structures are so overgrown,

I wonder whether it might be

a deserted medieval village.

NARRATOR: Elsewhere in the U.K.,

there are eerie relics of abandoned villages,

their inhabitants forced to flee by one of

the many terrors that stalked the land in medieval times.

Plagues, witchcraft, famine.

It could be any number of reasons

why people would leave their village.

So if that is what happened here, then we've got to

figure out why they left.

NARRATOR: Such was the prevalence of pestilence and war

during the medieval period that, at some points,

life expectancy was just 17 years.

During the 14th century alone,

the Great Famine kills millions and leads to

cannibalism and infanticide across Europe.

Barely 30 years later, the Black Death wipes out

a further 25 million people,

a third of the entire continent's population.

CAVELL: Disasters would hit, and it would

force people to have to move on.

So we get the remnants of these ancient societies,

and this might be one of them.

Okay, I think this is one

of the shapes from the satellite image.

Wow.

This is a massive wall.

Absolutely vast in width.

Much higher than I was expecting.

NARRATOR: The structures are too big to

be the remains of a medieval settlement.

Instead, they appear to have been used to conceal

or shield something that once stood in their center.

BRADSHAW: There's space here for something,

and that looked like an entranceway to me.

I think these four walls were

protective barriers for a structure that

would have sat deep in the middle.

Well, I wasn't expecting to find this here.

This is a early 20th-century building,

and it's only a few hundred feet from the squares,

so that would make them built around the same time.

NARRATOR: Nearby stands another structure not

visible in the satellite image.

Wow.

This is absolutely vast.

It's without doubt a fuel-burning device,

probably coal.

NARRATOR: A chimney of this size would once

have helped generate immense amounts of energy.

This site, it appears, is what is left

of a giant industrial complex of some kind.

The question is, why is it here

in the middle of sand dunes on a beach in Cornwall?

And how is it linked to the other structures in

this complex?

NARRATOR: A series of strange lines on

the western perimeter of the site offer clues.

Gosh.

There's something...

epic going on here.

NARRATOR: The rows of concrete planks, around 40 feet in

length, sit on the highest part of the complex.

BRADSHAW: They might be

similar to what I've seen in other industrial complexes.

I suspect that they would have these absolutely vast barrels

sitting here so these would act as

stabilizers and then connected via pipes that lead from here

down the hill to the other structures

in this landscape.

NARRATOR: Bradshaw believes the barrels stored here were used

to feed chemicals into the giant square structures,

and the size of their walls suggests

that whatever flowed into them was extremely dangerous.

If I'm right, then I'm standing

in an explosives factory,

which is pretty incredible, really.

NARRATOR: The site's remote coastal location

and layout lends weight to this theory.

BRADSHAW: I think that these series of walls were

specifically designed

to stop a chain reaction happening if there was

an explosion.

NARRATOR: Local historic records confirmed that this facility

was once known as the dynamite works,

and they also revealed that it played a key role in events

that would change the course of human history.

MORGAN: It led to the deaths of millions of people,

and it created shock waves that are still guiding

the world in which we live today.

NARRATOR: Coming up, how the site

revealed from space unleashed Armageddon.

Its unassuming appearance belies its potential

for carnage and chaos.

NARRATOR: And the mystery of the vanishing volcano.

Millions of tons of lava, like that.

Abracadabra.

NARRATOR: Rebecca Bradshaw is on Britain's Atlantic Coast,

drawn by a series of strange shapes revealed from space.

She has uncovered the decaying remnants of

a massive early 20th-century explosives factory.

BRADSHAW: This really is such an incredible sight,

but it's also a relic of death and grief

for millions of people.

MORGAN: Looking into the historical records,

this is one of only a handful of explosives factories

in the U.K.

This site actually goes back more than 100 years,

predating even World War I.

NARRATOR: The records reveal that the site opens in

1889, making dynamite for the local mining industry.

[explosion blasts]

But it's the role that it played in events

on the Western Front,

the main theater of conflict of World War I, that helps

define the course of history.

MORGAN: Here we have an amazing piece

of history that's been captured from space.

It plays a critical part in rewriting

the political map of all of Europe.

[explosions blasting]

NARRATOR: Over a four-year period, the Western Front's

French and Belgian battlefields claimed the lives

of nine million people.

[explosions blasting]

But what makes it so pivotal to military history

isn't just it's unprecedented scale,

but the way in which it is fought.

Military technology undergoes a quantum

development during the First World War.

This is not the era of old muskets and cannon.

This is the era of super precise artillery and rifles.

Warfare as we know it

will never look the same.

NARRATOR: Gunpowder, which has been in use for almost

1,000 years,

is too dirty and unstable for this revolutionary weaponry.

A race begins to produce a new

explosive to help them maximize their killing power

on the World War I battlefields.

WALTERS: You've got chemists working overtime,

trying to perfect new, deadly forms of explosives.

So, you know, the war is in

the laboratories as much as it's on the battlefields.

NARRATOR: Declassified British military files

reveal that during the early years of the First World War,

the factory in the image begins

production of a groundbreaking explosive called cordite.

Cordite got its name because of its appearance.

It almost looks like sort of dried spaghetti noodles.

Its unassuming appearance, however,

belies its potential for carnage and chaos.

NARRATOR: Cleaner, cheaper, and more stable than gunpowder,

cordite helps to transform

the range and rate of fire of the British arsenal.

Cordite was seen at a time to be this new super explosive

in the trenches.

MORGAN: We see single-shot rifles being replaced with

magazine repeating rifles that fire bullets that are 30 times

more likely to hit their target than before.

NARRATOR: The new explosives being made by both sides

mean a million machine guns will fire

a billion bullets over the course of the war,

mowing down a generation of young men.

But their impact on the use

of artillery is even more cataclysmic.

[explosions blasting]

Accuracy increases by 95%,

and shells weighing thousands of pounds rain down

on enemy troops up to 80 miles away.

[explosions blasting]

JANULIS: The hope was that this technology would ensure it was

a quick war, but that's not what happened.

It led to the most brutal warfare on the planet

in human history.

PAVELEC: The Western Front became dominated by artillery

that each side just fired at each other on a regular basis

day after day.

NARRATOR: The increasing use of artillery sees the war descend

into a muddy, bloody deadlock.

During the Battle of Verdun, 40 million artillery shells are

unleashed, meaning that during the 10-month-long engagement,

the most territory gained by either side is just five miles.

WALTERS: The reason why the First World War is

this horrific bloodbath, you've got

20,000 people dying in an afternoon, is because of

these weapons.

NARRATOR: To shield themselves from this aerial hell,

soldiers dig a staggering 25,000 miles of trenches.

But they still die at the rate of 6,000 per day,

a third of them from the diseases and infections that

flourish in the filth and gore of trench warfare.

PAVELEC: World War I becomes a war of attrition,

carnage on an industrial scale.

NARRATOR: Such is the apocalyptic number of shells

and bullets being unleashed on

the Western Front that the factory in the image can't

keep up with demand.

Britain's children provide an unusual solution.

One of the raw materials needed to produce cordite

is acetone,

and that was something that was in short supply.

But then it was found that

horse chestnuts and acorns could provide it.

And so there's this massive campaign launched,

and British schoolchildren are sent out to collect

horse chestnuts and acorns.

And unbeknownst to them,

their efforts are being used to support the production of

this deadly explosive.

NARRATOR: The role the explosives factory played

in Britain's eventual victory in World War I

can still be seen, etched into the fields of northern

Europe and onto the graves of the millions

who perished there.

And while it is now being swallowed by the dunes,

Bradshaw is hopeful its legacy will not fade from

history so easily.

For me, this site is a real monument to our forefathers

and foremothers who sacrificed

so much so that we could live in the world that we do today.

NARRATOR: Coming up,

the altar of the shapeshifting eater of islands.

CAVELL: He is a particularly fearsome God.

He's the God of War.

NARRATOR: And the guardian of the galaxy.

This is really a critical

element in our defense and surveillance.

NARRATOR: November 11th, 2019.

The WorldView-3 satellite scans

the northern tip of the Big Island of Hawaii.

This shows a huge rectangular enclosure with what looks

almost like a tipped-over tombstone lying down inside it.

CAVELL: It's an enormous structure.

It's just this

stamp in the middle of pretty much nothing else.

NARRATOR: Analysts dial up the magnification on

the giant 40,000-square-foot stamp in the landscape.

Closer inspection does reveal some clues.

The massive walls were actually built

out of the local rock, basalt.

Seeing that immediately suggests to me ritual.

NARRATOR: The mystery structure is constructed from

boulders taken from a nearby volcano,

one of five that sit on this island.

The people here have long held these mountains as sacred,

believing them to be the home of Pele,

the goddess of fire and creator of this archipelago.

The Hawaiians believed that they were surrounded by

supernatural beings, by spirits

you could find in the mountains and the valleys

and the shores.

NARRATOR: The irregular alignment of

the structure's walls suggests

it was built to honor these supernatural forces.

Before European contact, Hawaiians would

build their temples as parallelograms.

It was a symbolic and spiritual thing

to build it this way.

We're looking at an ancient Hawaiian temple,

and it's located in a very imposing,

visible place in the landscape so people would always be aware

of its power.

NARRATOR: Indigenous Hawaiians believe in thousands of gods

who are ruled by four supreme deities.

Their religions trace their roots back to those of

the Polynesian explorers who first arrived here

around 1,500 years ago.

Hawaii is one of the most remote places on Earth,

and one of the mysteries is how anyone ever discovered

these little pinpricks in the ocean.

NARRATOR: Having navigated millions of square miles

of open ocean,

the Polynesians begin constructing ritual landscapes

to venerate and appease

the gods that they worshipped and yet also feared.

HORTON: The Polynesians that came here

had a pantheon of Gods,

and these were given huge prominence in Hawaiian society.

CAVELL: One of the legends has it that

the Tahitian or a Samoan warlord

brought the idea of this structure with him,

and he was the one behind the construction of this temple.

NARRATOR: The story goes that the first temple

to stand at the site in the image

was built by a race of little people,

known as the Menehune.

Thousands of men were needed to construct this temple,

thousands of them, and it took one night,

according to legend.

NARRATOR: Studies suggest that in the 12th century,

the temple is rebuilt, and its walls heightened to 30 feet.

It is dedicated to the God Ku,

a deity who shapeshifts between human and shark form

and is known as the eater of islands.

He is a particularly fearsome God.

He's the God of War.

HORTON: Ku was probably the most important of these Hawaiian

gods, and only the king,

the priesthood, and the highest nobles were allowed

access to the temple.

BELLINGER: What really sets the God Ku apart from the others

in the Hawaiian pantheon is that he was the only God

who demanded human sacrifice.

NARRATOR: These gruesome rituals take place on

a boulder visible in the image.

While much of the blood letting is carried out to

appease the eater of islands,

others are slain to enforce a strict local code of conduct

known as Kapu.

Every aspect of everyday life is

strictly ordered according to these laws.

And if one breaks Kapu, one is condemned to death.

These sacrifices weren't simple

cut the throat, let them bleed sort of events.

They skinned and de-boned their victims like livestock.

One of the more grizzly aspects of this process

was some of the flesh that was removed from the bodies was

then consumed by the people

involved in these rituals.

NARRATOR: During the 17th century,

the eater of islands plays a key role

in events that change Hawaii forever.

One of the figures intimately associated

with this temple is King Kamehameha.

BELLINGER: In the picture, we can see lines about 2,000 feet

away from this temple structure,

and that's where King Kamehameha was actually born.

NARRATOR: Kamehameha was a warrior king,

said to be 7 feet tall.

At the time of his birth in 1736 A.D.,

Hawaii had been separate kingdoms for 1.5 thousand years.

Kamehameha spent a lifetime warring with other chieftains,

sacrificing many of those he defeats at the temple

to his war God.

Some might believe that Kamehameha's power

actually drew directly from this temple to Ku.

JANULIS: Apparently, the power of the temple

worked for him, because he was the first person to ever unite

all of the Hawaiian Islands.

NARRATOR: By 1810,

Kamehameha is ruler of all Hawaii,

and while the blood-soaked temple dedicated

to his war God is crumbling to ruin,

its extraordinary role in

the history of these islands lives on.

It's incredible that this structure that's so ancient

and so utterly entwined

with all of Hawaii's most important mythology

and history is still visible from space.

NARRATOR: Coming up, the pit of horrors.

It's amazing that anybody survived.

NARRATOR: And Earth's $3 billion force field.

If anything goes through it, we know about it.

NARRATOR: April 9th, 2019.

A satellite scans the mountainous interior

of the East Asian country of Taiwan.

It's kind of an enduring image that all of us have

of the Far Eastern Asia is a rice paddy cut into

a hillside.

NARRATOR: As it moves towards a coastal area,

it captures patterns that seem out of place.

KOUROUNIS: The fact that these lines are so straight

and so parallel tells me

that they were not created by a Taiwanese farmer.

It just doesn't look right.

HEIMLER: It does sort of resemble a face.

You've got two eyes on top

and steps almost descending downwards.

NARRATOR: Further aerial images

reveal details of the mystery structure.

MORGAN: It bears the hallmarks of military architecture,

so perhaps from a bygone era,

this was some sort of a coastal fortification.

NARRATOR: The crumbling structure doesn't

resemble Taiwanese military architecture,

so historians speculate that it was built

in the 17th century,

a time when the island nation

is ruled by a foreign power,

not a country, but a company, whose

wealth and influence are unparalleled in history.

Taiwan was then known as Formosa,

and it was a protectorate of the Dutch East India Company.

This company was huge.

It had interests that stretched all the way from

the Persian Gulf to Japan.

NARRATOR: Founded to protect Dutch trade in the Indian Ocean,

at its peak, the company

has assets equivalent to $7.9 trillion.

WALTERS: Imagine every big company we know today,

roll onto a big ball, and you still don't get

anywhere near the wealth and power of

the East India company.

NARRATOR: The conglomerate and its rival,

the British East India Company,

employed tens of thousands of people and use massive

private armies to protect their interests.

Their vast wealth is generated from trade in spices,

tea, and another very different product.

MORGAN: They created an additional revenue stream

in the form of this smuggling operation

by which they were selling opium

illegally into China.

WALTERS: They were shipping drugs around the world

and making an absolute fortune out of them.

NARRATOR: Thanks to these companies,

by the middle of the 19th century,

China is consuming around 5,000 tons of opium a year,

and a third of the population are hooked on the narcotic.

They make Pablo Escobar look like small fry.

It was the most extraordinary example

of capitalism run right.

MORGAN: This could potentially be one of those opium processing

plants, and if this was,

it would make a lot of sense that you built fortifications

to protect it.

NARRATOR: Further analysis reveals the site

is leaching liquids that have changed

the color of a nearby waterfall.

It suggests the structure isn't

a legacy of these giant trading companies.

HEIMLER: There's some pretty strange colors going on there.

This tells me it's probably toxic.

This must be some kind of industrial site

or maybe a mine.

NARRATOR: Local historic records shed more light.

In 1933, the Japanese Imperial Army set up

a copper smelting and mining operation here in Taiwan.

NARRATOR: In the early 1930s,

Japan is ramping up its industrial

and military strength,

but doesn't possess enough natural resources

to power this growth.

WALTERS: She desperately needs ironwork,

she desperately needs oil,

and what she also needs is copper.

NARRATOR: Taiwan, which is under Japanese rule,

has vast reserves of the metal.

Soon, the mine and smelter in the image are helping

to produce the weapons of war

that will unleash hell on Pearl Harbor in

the Pacific.

[explosions blasting]

If you're gonna shoot guns, you got to have copper,

and this is the facility that provided the Empire

of Japan all the copper that it would ever need.

NARRATOR: By the start of World War II,

Japan is producing 165 million rounds of ammunition

and 5,000 aircraft every year.

To keep up with demand,

the following year, authorities bring in 1,000

prisoners of war to work the mine.

In order to get those prisoners of war there,

they packed them onto what became known as hell ships.

MORGAN: Men were dumped into the cargo holds,

where the conditions were wretched beyond

human imagination.

HEIMLER: Make no mistake,

the hell ship deserved its name,

but this mine where they were going,

it was actually even worse.

NARRATOR: In the mine, the prisoners toil for up to

12 hours in almost complete darkness

in temperatures of 130 degrees Fahrenheit or more.

Injuries, maltreatment, and disease will kill

a third of them,

a death rate 20 times higher than in German

prisoner of war camps.

They're used to their prisoners of

war to work themselves to death effectively.

It's amazing that anybody survived.

NARRATOR: The sweat and blood shed by the prisoners

here produced tens of thousands of tons of copper,

which fuel the slaughter of American troops in the Pacific.

But even as Allied victory draws ever nearer,

they discover their ordeal is far from over.

HEIMLER: Once it's clear that Japan is going to lose the war,

the order goes out to exterminate

these prisoners en masse.

NARRATOR: Mercifully, at the last hour,

the POWs are granted a reprieve.

The place that inflicted so much terror

and pain on them remains a monument to barbarism,

visible from space.

It's a massive, grim reminder of man's capacity for cruelty.

**

NARRATOR: Coming up, radioactive train wrecks.

MORGAN: They have to be able to endure anything

because of what they're going to be carrying.

NARRATOR: And the land of the cannibal volcano.

It's no surprise that many revere

and fear this extreme force of nature.

NARRATOR: February 22nd, 2018,

a satellite traveling at 17,000 miles per hour

over southern New Mexico

captures an image of something strange in

the landscape below.

Here we are in the middle of the New Mexico desert,

and what I'm seeing is what appear to be

gashes in the earth.

These are a series of perfectly straight lines

in the middle of nowhere in the desert.

It just seems really weird.

NARRATOR: Closer analysis reveals

the giant lines appear to be rows of metal tracks.

It's got to be some sort of a government testing facility,

I'm thinking, but what the heck are they testing?

NARRATOR: Martin Morgan uncovers

a clue in local government records.

MORGAN: The Department of Energy uses steel tracks to test

the casks that are used to transport nuclear material.

So maybe these strange lines in

the desert are associated with that.

[train whistle blows]

NARRATOR: Over the past decades, the U.S. government

has transported 100,000 tons of

nuclear waste in giant containers across the country.

To ensure these containers can survive any kind of calamity,

New Mexico based scientists place them on tracks

and test them to the point of destruction.

[crashing noises]

They hit them with locomotives going full steam, and then they

put them on trucks and smash them into walls

going 80 miles an hour.

[crashing noises]

These casks have to be able to endure

anything because of what they're going to be carrying.

It would make sense to carry out that

kind of testing in the middle of nowhere.

[crashing noises]

NARRATOR: Yet when NASA planetary scientist Pascal Lee

examines the site in the image, he reveals

it has an even more critical origin.

LEE: You're not seeing a row of train tracks.

What we're looking at here are

antennas laid down on the ground.

It is actually one of the archaeological sites,

so to speak, of the dawn of the Space Age.

NARRATOR: Lee believes the satellite has captured

a clandestine facility that played

a vital role in America's quest to conquer space

for over half a century.

LEE: This is one of the stations of

a network that was created by the military

called the Space Fence,

and it was designed to track foreign objects in the sky.

NARRATOR: The catalyst for the Space Fence is the Soviets'

1957 launch of Sputnik 1, the first satellite in history.

[indistinct talking in Russian]

NARRATOR: The Communist coup spurs NASA to accelerate

its own space program,

sparking a frenzy of launches that soon become a competition

of political ideology as much as one of technology.

HEIMLER: It's hard for us to imagine the tension between

the Soviet Union and the United States

during the Space Race.

NARRATOR: When the USSR launches

its first intercontinental ballistic missile,

concern grows about the U.S.'s ability to detect and track

the escalating amount of hardware in orbit

around the planet.

MORAN: For U.S. military and intelligence agencies,

this is really a critical element in our defense

and surveillance.

You don't want to mistake

a regular airliner for an incoming missile

from Russia, for example.

NARRATOR: In 1961, the U.S. Navy takes action,

constructing nine giant antenna and receiver stations

such as the one seen in the image.

By beaming radio waves into space,

they create 5,000-mile-long

electromagnetic barriers that dissect Earth's orbit.

If a foreign object passes through these barriers,

receiver stations on the ground alert authorities.

If anything goes through it, we know about it.

You could tell how fast the object was traveling,

how high it was, and also what size it was

based on the intensity of the echo.

The U. S. Military and U.S. intelligence agencies

see the Space Fence

as a critical early warning and defensive system.

NARRATOR: As the Cold War thaws, the specter of a possible

Russian nuclear attack recedes,

but the Space Fence must instead deal with a new,

equally challenging threat.

Since the 1960s, we've put so many more

satellites up into the sky,

and there's been a greater amount of debris.

NARRATOR: With the advent of spy and communications satellites,

up to 1,200 pieces of hardware are launched into space

each year.

As soon as they reach the end of their technological

lifespan, they can break apart,

creating orbiting 17,000-mile-per-hour bullets

that weigh up to a ton.

Any kind of space debris could collide with one of our

satellites and destroy a vital component of our military

or communication systems.

NARRATOR: The Space Fence provides satellite

operators with mission critical debris data.

On 27 separate occasions,

it has also proved vital to the survival of

the International Space Station and those living

on board.

MAN: Ballistic specialists received data

that showed a conjunction

with a small piece of a Russian Kosmos satellite.

When there is a predicted impact,

we can get out of the way or even show a shielded side to

the incoming debris.

NARRATOR: In 2020, after more than five decades of service,

this vanguard of space surveillance is replaced with

an upgraded defense system.

Yet it continues to gaze up at

the spacecraft it kept watch over for so long.

It's amazing to look down from space and see a system that

was built to protect the very satellite

that we're looking down from.

NARRATOR: Coming up, the mountain that ate itself.

When the volcano goes quiet,

it's like that calm before the storm.

NARRATOR: November 25th, 2018.

The Sentinel-2 observation satellite scans

the Pacific Ocean 1,000 miles east of Australia.

As it passes over the Vanuatu archipelago,

it snaps this image of the volcanic island of Ambrym.

FANARA: Wow, it looks like there are stars or something

just, like, coming through the mountain.

KOUROUNIS: There are these two orange glowing dots,

almost as if this island has a set of eyes that are looking

up into space.

NARRATOR: The craters of both volcanoes are brimming

with increasing amounts of 2,000-degree-Fahrenheit lava.

Whenever a volcano is changing in some way,

that's usually a big red flag to me saying that,

yeah, you probably want to keep your distance.

This volcano looks like it could erupt at any time.

NARRATOR: Yet when the satellite passes over the island

three weeks later,

it captures an image that baffles scientists.

KOUROUNIS: There's something very unusual going on.

Millions of tons of lava just disappeared like that.

Abracadabra.

NARRATOR: Ambrym has long been shrouded in mystery.

The locals know it by another name --

Black Island.

DENNIE: There is a story of back in 1913 a local tribe

actually asking for the volcano

to erupt and crush its enemies on the other side

of the island.

NARRATOR: During that same year, the largest eruption in

the South Pacific in four centuries

engulfs whole villages in molten rock.

KOUROUNIS: On Ambrym,

the dominating feature of

the landscape is this active volcano.

So it's no surprise that many of them

revere and fear this extreme force of nature.

NARRATOR: Experts believe the disappearing lava

could be connected to

a massive earthquake which struck the island around

the same time.

DENNIE: You can really see the impacts of

this event on the surface of the island.

There were roads that were broken,

structures were damaged.

NARRATOR: An earthquake can often spark a powerful eruption,

but in this instance,

it instead triggered an extraordinary

geological event.

This is called [indistinct] cannibalism, where literally,

the volcano eats itself.

FANARA: This is an incredible phenomenon,

a volcano actually swallowing its own lava.

It's really weird.

NARRATOR: Prior to the volcano turning cannibal,

its craters are filled with enough molten rock

to fill approximately 160,000 Olympic-sized swimming pools.

There are only a handful of places on the entire planet

where you have volcanoes with lakes of lava,

and it just so happens that there are two

on this one island -- that's really unusual.

NARRATOR: When the quake hits, it creates deep fractures

in the bedrock under the giant lava lakes.

KOUROUNIS: Any time you shake a volcano violently,

you're disrupting the plumbing inside the mountain beneath

those lakes of lava.

DENNIE: When these fractures open up, the magma literally

gets pulled back into this void and out of the lake above,

because it's not supported by any pressure below.

NARRATOR: The cataclysmic forces unleashed by this volcanic

cannibalism changed

the entire shape of the eight-mile-wide caldera

and raise the height of the island's coastline

by several feet.

We were very fortunate to capture this event.

It's very rare.

NARRATOR: The latest satellite images show no

signs of activity in the craters,

but scientists know there is still good reason to fear

Black Island.

KOUROUNIS: It's an unpredictable volcano

that has devastating, huge explosions.

When the volcano goes quiet,

it's like that calm before the storm.