All language subtitles for What.on.Earth.S10E02.1080p.DSCP.WEB-DL.AAC2.0.H.264-BTN_track3_[eng]

NARRATOR:
They're watching you.

More than 5,000 satellites
circle the Earth.

Every day,
they uncover new

mysterious phenomena
that defy explanation.

From the skies,

the hunt for the lost
Viking army.

I think this is where
the kings were being buried.

NARRATOR:
The lagoon of horrors.

This water is basically
a poison stew.

NARRATOR:
And the CIA

versus the super warriors
of the ancient world.

You name it,
they were prepared for it.

NARRATOR: Baffling phenomena,
mysteries from space.

What on Earth are they?

[theme music playing]

Derbyshire,

a deeply historic county
in the center of England.

200,000 years after humans
first walked these lands,

Mark Horton has been
drawn here

by a mystery revealed from
the skies.

This is a fascinating image.

It's of a shape that I've
never really seen before.

NARRATOR: An aerial laser scan
of a patch of remote

forest has revealed groups of
circular structures,

lost to history.

HYMEL:
What we're looking at here

seem to be clusters of almost

what looks like pimples
on the ground.

KOUROUNIS: There are so many
lumps and bumps.

Looks like this countryside
has got chicken pox.

NARRATOR:
Elsewhere across the U.K.

are similar-shaped structures,

the earthen tombs of
warriors and chieftains,

casualties from 5,000 years of
this country's long,

bloody history.

Horton thinks these, too,
are burial mounds,

but something about them
doesn't make sense.

What's really exciting about
this particular group

of mounds is that
they're tightly packed.

I've never ever seen
examples like

that anywhere
in the British Isles.

NARRATOR: This arrangement could
suggest that this patch of

forest was once a place of
mass slaughter.

HYMEL: Because we're looking at
so many mounds,

it could be the result of

a major battle,
where they bury the bodies

near where they fell.

I think this is
the -- the woodland.

It's massively
impenetrable and thick,

with barbed wire
and everything -- somebody...

clearly doesn't want
anyone to get in here.

Hi, it's Mark here. Hiya.

Surrounded by...

NARRATOR: Horton learns that
the mounds sit on

private land, and entry is
strictly prohibited.

Are you saying that the public
aren't allowed in here at all?

So frustrating.

But another contact
does have some better news.

That's really interesting.

Can I come over and see them?

NARRATOR: Human remains
have been discovered

near the site in the image.

Dr. Cat Jarman is analyzing
them for clues.

These skulls are
absolutely fantastic.

Where were they
actually found?

These skulls here were all
found in a mass grave

really close to the mounds.

There was almost 300 of them
all together,

all jumbled up.

NARRATOR: Dr. Jarman's
studies have revealed

the mass grave is a relic of

one of the bloodiest periods
in England's history.

These skulls actually
date to the Viking Age.

So the mounds I've seen on
the image could be Viking.

I think that's very possible.

NARRATOR: The Vikings arrive in
England in 793 AD, spurring

a wave of pillage and terror
that lasts for over

two centuries.

And what Dr. Jarman's work has
shown is that these remains

and the ones
hidden in the woods

could be
those of perhaps the most

feared Norsemen of all.

All the new scientific
evidence is really very

strongly suggesting that this
is the Great Heathen Army.

NARRATOR: The Great Heathen Army
was a monstrous force

of Vikings who invaded England
in 865 AD.

[men shouting]

Its arrival marks
a dramatic escalation in

the decades of bloodshed that
had preceded it.

In the beginning, the Vikings
were primarily smash

and grab Raiders,

but in 865, that all changed.

We're talking thousands,
and they had

the express goal of taking
over England.

HYMEL: This army is organized,
it has a single purpose.

They're not looking
to pillage,

they're looking to conquer.

NARRATOR: At the time,
England is ruled

by four separate kingdoms,

Northumbria, Mercia,
East Anglia, and Wessex.

The ninth century Anglo-Saxon
Chronicles describe how

the heathen warriors
quickly conquer

two of these realms,
slaying or subjugating

all who stand in their path.

We know that they were up

against some really strong
Anglo-Saxon forces.

So we are talking
about substantial

number of people moving
through the landscape.

NARRATOR: The army is led by
Ivar the Boneless,

son of the legendary
Viking hero,

Ragnar Lodbrok
and a warrior of

incredible cruelty
and ferocity.

[man shouting]

It was a wave of terror
in human form,

and there wasn't a thing
you could do about it.

[men shouting]

NARRATOR: Historians believe
the Heathen Army

contained around
10,000 warriors,

a force without
parallel in Viking history.

Yet few traces of it
have ever been found.

HYMEL:
The Great Heathen Army,

it's steeped with mystery,
because there's

no real physical evidence of
its existence.

NARRATOR: However, near
the site in the image,

Jarman has discovered
possible evidence

of the army's presence,

pieces of Hnefatafl,
a game

which its warriors reputedly
played between battles.

Hnefatafl is a board game
a bit like drafts or checkers.

So they're the smoking gun
of the Great Heathen Army.

Absolutely -- wherever
the army has been,

we are also finding
these gaming pieces.

NARRATOR: Horton is convinced
that the graves in

the image hold the remains of
the Norse invaders.

The number buried there
suggests that something

of great value to them
must lie nearby.

The question is,
why are the Vikings

coming here to the middle
of England?

What would have attracted them
to this place?

NARRATOR: Coming up,

into the Vikings chamber
of secrets.

Once they captured this,

they've captured the soul of
Saxon England.

NARRATOR:
And terror from the skies.

[explosion blasts]

One wrong move at the wrong
moment will get you dead.

NARRATOR: In Derbyshire,
England, Mark Horton is on

the trail of
the Great Heathen Army,

a force of some 10,000 Viking
warriors who

rampaged across the country
in the ninth century AD.

This was the army that
successively defeated

each of the kingdoms
of Anglo-Saxon England

and installed their own kings.

♪

NARRATOR: Aerial scans suggest
that hundreds of

these legendary Norsemen lie
buried in nearby woods.

The question, to me,
is why did they

come here at all to this area
in these midlands?

NARRATOR: Horton turns
to 3D surveys, which

reveal the remains of
ancient waterways

the Vikings used to plunder
the area around the image.

There's one here which is
really interesting,

because that comes

alongside what appears to be
a small settlement or a village.

NARRATOR: Horton tracks
the waterway from the mounds

to the settlement.

I can see the church.

This is actually beginning to
make sense.

NARRATOR: In Viking-era England,
churches take 10 percent of

the local population's
annual earnings in taxes,

and they are filled with gold
ornaments and valuables...

...sacred to
the Christian Saxons,

but not to the pagan Vikings.

[men clamoring]

I can imagine the excitement
of those Vikings

rowing up this river

and realizing that this
was a treasure for the taking.

NARRATOR: Much of the church
appears to have been

built after the arrival of
the Great Heathen Army,

but not all.

Gosh, there's a little --
little passage

that takes us
right underground.

NARRATOR: Horton finds himself
in a 250-square-foot

subterranean chamber.

HORTON: This is
an extraordinary space.

I think that this crypt
must be Saxon,

and then the medieval church
has been built on top.

NARRATOR: Historical records
confirm that this crypt

was constructed in
the 8th century AD,

meaning it is one of

the oldest Christian sites
in the country.

What makes it such a target
for the Heathen Army is that it

sits in the town of Repton,

the capital of Mercia,

the most powerful of the four
main Anglo-Saxon kingdoms.

Mercia was a rich kingdom.

This is where the greatest
concentration of power,

authority, and money rests,
and the Vikings knew that.

NARRATOR: When the Great Heathen
Army arrives in Mercia

in 867 AD, two of
the kingdoms,

East Anglia and Northumbria, had
already fallen to its swords.

To complete their conquest,
the Vikings need Mercia's

Christian riches to bolster
their war chest.

Yet as Horton explores
the crypt,

he finds clues that it
contains something of much

greater value to the Vikings
than gold and silver.

You've got
these little recesses,

one, two, and three recesses.

That reminds
me of places where coffins,

or sarcophagi,
would have been placed.

NARRATOR: The size of the crypt
and its ornate decoration

suggests that it was once
the resting place

of the most powerful people
in the kingdom.

I think that this
isn't just a crypt.

This is a royal crypt.

This is where the great kings
of Mercia were being buried.

NARRATOR: Anglo-Saxon Chronicles
confirmed that this crypt once

contained the remains of
three Mercian royals,

making it perhaps the greatest
prize for the invading Vikings.

HORTON: Not only would it be
dripping with treasures,

but actually,
more importantly,

once they've captured this,
they've captured

the soul of Saxon England.

That explains
why some of their dead

are buried in
those mounds.

[men shouting]

NARRATOR: In 874 AD,

the heathen warriors
conquer Mercia and descend

on Wessex,
the last Saxon kingdom.

There were thousands of
Vikings in a coordinated effort,

acting as a unified army
coming right at them.

NARRATOR: The two armies meet at
the battle of Eddington

where the Wessex king,

Alfred the Great, finally
defeats the Norsemen,

ending their campaign
of conquest.

Alfred goes on to
unite the four kingdoms,

and the bodies of

the vanquished heathens are
swallowed by the earth before

being revealed once more
from the skies.

HORTON: What I've seen has made
me totally certain that

the Vikings came here,

and in so doing,
changed the course of

English history.

NARRATOR: Coming up, the Navy's
multibillion dollar secret.

This is something being used
for very special purposes.

NARRATOR:
And Hawaii's mystery cipher.

ALBERTSON: It reminds me
sort of like a chess game.

I don't get it.

NARRATOR:
September 2020,

a satellite
captures this image of

New Jersey's 7,400-acre
Lakehurst Naval Base.

HYMEL: We're looking at
what looks to be an airstrip.

No surprise there.

But north of it,
we see these five lines,

almost like a section of
a fan,

and a cutout sort of
circular pattern.

MORGAN: These shapes don't seem
like they go together,

and I'm not sure what
they're for.

♪

NARRATOR: Lakehurst is one of
the U.S. military's

most sophisticated
testing facilities,

with a history stretching back
over 100 years.

Military records reveal that
the strange circle in

the image is the legacy
of its darkest hour.

Despite the fact that this is
a Naval Air Research Center,

what is interesting is that
the big circle in

the image is the landing site
of the Hindenburg.

NARRATOR:
When launched in 1936,

the 800-foot-long
German airship,

partly funded by the Nazis,

was seen as the future of
luxury air travel.

In a cabin sitting below
some seven

million cubic feet of highly
flammable hydrogen,

50 passengers
enjoy a piano bar,

fine dining, and incredibly,
a smoking lounge.

HYMEL: The blimp is
ideally suited for this task.

It can stay elevated
for long periods of time

without any kind of heavy
fuel consumption.

NARRATOR: On May 6th, 1937,
the mammoth airship

approaches Lakehurst
after completing

a transatlantic flight.

As it attempts
to dock at the circle

in the image, it ignites,

and the resulting inferno
claims 36 lives.

ALBERTSON: In the middle,
they would have had a hook

that the airship would have
hooked on to be stable and land.

It also would have discharged
any static electricity

into that when it landed,

which eventually led to
the crash.

NARRATOR: The strange lines
to the south of

the crash site have
a different origin.

MORGAN:
When you punch in close,

you can see that these
fan-shaped lines look like

airstrips maybe,
but they converge.

CAVELL: You can actually see
tracks in the middle of them.

This is something being
used for very special

military purposes.

NARRATOR:
Declassified records confirm

the tracks are used to help

the military prepare for
the extraordinary challenges

posed by naval aviation.

Naval aviation really means
planes flying off

the deck of
a carrier or landing.

CAVELL:
It's probably one of the most

dangerous occupations
to be involved in.

Just about every aspect of
it could

be deadly if you slip
for one minute.

NARRATOR: The first attempt to
launch a plane from a warship

takes place in 1910,

just seven years after the
Wright brothers' maiden flight.

Over the following decades,

thousands of Navy pilots die
attempting

this perilous maneuver.

ALBERTSON: Think about what it
takes to land aircraft, right?

Now go to sea
with pitching decks,

rough seas of 50 feet
or greater --

one wrong move
at the wrong moment

will get you dead,
and this happens every year.

NARRATOR:
Following World War II,

the advent of supersonic jets
forces the Navy

to introduce a new generation
of carrier deck technologies.

The systems on an aircraft
carrier that launch

and catch aircraft

are incredibly complex,
and the catapult is probably

the most important.

NARRATOR: The latest generation
of aircraft carriers

uses electromagnetic
launch systems.

Before being
installed on flight decks,

the systems are tested to
the point of destruction

at the site in the image using
rocket-propelled sleds.

MORGAN: The jet car track site
provides the ability to test

at high speed on the ground

without having to
hazard expensive aircraft

or lives in an airborne test.

NARRATOR: On board, these
systems propel $100 million

fighter jets 0 to 165 miles
per hour in two seconds,

subjecting pilots to
a dizzying 4 Gs of force.

MORGAN: You can get a large
twin engine jet fighter, like

an F-18, airborne in a span of
a couple hundred feet.

NARRATOR: When pilots return
from their missions,

Lakehurst-designed
cable systems stop

a 150-mile-per-hour
jet in less than 300 feet,

transferring four times
its takeoff weight

into the fuselage.

CAVELL:
They have arrestor cables

that can catch the tail hook on
an aircraft,

and the only pieces
of equipment

stopping that aircraft
from actually plowing

right off the other end
of the deck.

ALBERTSON: Room for error does
not exist in this business.

It's precision,
life or death stuff.

NARRATOR: Eight decades ago,
the shapes

and the image were a place of
death and terror.

Today, they are vital
to protecting

the lives of around
7,000 Navy top guns.

CAVELL: It really is a pretty
amazing facility

at the cutting edge of
military technology.

NARRATOR: Coming up,
China's mystery mega structures.

The spies go there
disguised as tourists

to figure out what
they actually are.

NARRATOR: And the strange tale
of the mule that tried to

save America.

CAVELL: It would be the first
line of defense

in any kind of an attack.

NARRATOR:
February 23rd, 2020.

A spy bird in orbit
over South China's

Fujian province captures
these structures

in the landscape below.

MORAN: This is a really
perplexing image.

You have this cluster of
shapes, but they don't seem

to be arrayed with any kind of
rhyme or reason.

MUNOZ: The location is
also really strange.

There's nothing around it
except for forests.

Someone really had to go to

a lot of effort to build
these things.

NARRATOR:
What's even weirder is that

declassified files
reveal the CIA

took a great interest in these
structures during the 1960s.

There are spy satellite images
of this exact location,

which means that CIA analysts
were actively looking at

this area
and wondering themselves

what was going on there.

CAVELL: The regularity of
the structures and the clustered

nature of them were red
flags to people

at the CIA who were really
worried about what kind of

strategic purpose
these might have had.

NARRATOR: The CIA knows
that China has just become

a nuclear power by

detonating a 22-kiloton
nuclear device

code named Project 596.

The intelligence agency fears
the mystery structures are

evidence of
a dramatic escalation

in their nuclear capabilities.

MORGAN: The government was
worried that the Chinese

had not only developed
an atomic bomb,

but that maybe
these structures were

the launch site for ICB EBs.

NARRATOR:
Washington is already engaged

in a silent yet hugely costly

conflict with Russia and is

about to send troops
into Vietnam.

Now, it has another

terrifying threat to
contend with,

one that it fears could strike
at any target within the U.S.

The reason that the government
had to be so concerned about

this was that
that would represent

a significant challenge to
the balance of power,

and the balance of power
circa 1965

was already pretty delicate.

NARRATOR: What's more,
China's secret development

of its atomic program
infuriates Russia,

creating a three-way standoff

between the nuclear superpowers.

MORAN: Here, you have
escalating tensions between

the U.S. and the Soviet Union,

and suddenly,
there's another country in

that region developing
its own nuclear capability.

It's worrisome for everyone.

NARRATOR: The Cold War satellite
images reveal thousands

of the silo-like structures
scattered across China.

If these are nuclear silos,

the CIA has got to find
out more.

MORGAN: Satellite photography
ultimately led to spies

having to go there
disguised as tourists

to figure out what
they actually are.

NARRATOR: The spies confirm
that the structures

and the image do serve
a military function,

but not the one the intelligence
agency expected.

CAVELL: What becomes clear is
that these are traditional

Hakka fortifications

and that many of them have
actually been around for more

than 600 years.

NARRATOR: The Hakka
are an ethnic Chinese

people whose origins are
shrouded in mystery.

According to folklore,

they are descended from
some of

the most celebrated warriors
in the country's history.

The Hakka have
traditionally been linked

to one of the greatest
and most warlike

of the Chinese dynasties,
the Qin dynasty.

NARRATOR: The Qin Dynasty
rises to power

during the 3rd century BC.

Its founder,
Emperor Qin Shi Huang,

conquers the six warring
states of China,

creating a unified country
for the first time.

On his death, a city-sized
mausoleum is built in

his honor, guarded by the 8,000
soldiers of the Terracotta Army.

HYMEL: Legends had it
that the Hakka people

are descendants of
warriors from Qin's army.

So there's this strong
connection between the Hakka

people and one of the great
emperors of China.

NARRATOR:
Unlike many Chinese,

the Hakka have
no traditional homeland.

As they move from province
to province,

they become viewed
as outsiders and are

forced to migrate south to
escape persecution.

The Hakka people in later
times found themselves

under attack.

The dangers of
just trying to exist

and raise a family were
very great.

NARRATOR:
After centuries of oppression,

a group of Hakka arrive in
Fujian province,

seeking refuge in its remote
mountainous interior.

Yet even here,
they find no sanctuary.

Bandits ran wild
in this region of China,

which made life pretty
miserable for the Hakka.

With everyone against them,

it's only natural to assume
that the Hakka would consider

building some serious defenses.

NARRATOR:
During the 13th century AD,

the Hakka begin constructing
the structures

in the image,
known as tulous,

to defend their families
from the constant

threat of violence.

MORGAN: What they developed was
a perfectly circular structure

with very robust outer walls

that could be used
for defensive purposes.

MUNOZ: These structures were
built to withstand anything,

fires, attacks,

you name it,
they were prepared for it.

NARRATOR: Each of the fortified
buildings is designed to

hold up to 800 Hakka warriors
and their families,

and enough supplies
and weaponry is to repel

anything from a surprise
attack to a prolonged siege.

They had a background,
a proud background, of a warrior

tradition, and these buildings,
they speak to that tradition.

NARRATOR: The strange structures
that so terrified the CIA

are, in fact, the legacy of

one of the most extraordinary
and resilient groups of people

in all of China.

What we're seeing here is
actually a testament to

the tenacity
and the sheer will

of a marginalized people
just wanting to survive.

♪

NARRATOR: Coming up,
the forgotten heroes

of Pearl Harbor.

It is a remarkable end to
a really dramatic tale.

NARRATOR:
And the mutant lake.

It's almost as if it's
a creature

living out its life cycle.

NARRATOR:
September 16th, 2020.

As a satellite orbits
above Ni'ihau,

the westernmost island
in the Hawaiian archipelago,

it captures this pattern
far below.

This is really
an extraordinary image.

RUBEN: All across are
these giant grids,

just crisscrossing lines
like graph paper

underneath the land.

NARRATOR:
The crisscrossing lines cover

some 370 acres
of a dry lake bed.

ALBERTSON: It reminds me sort of
like a chess game set out on

the ground --
I don't get it.

NARRATOR:
The lake is called Halulu,

named after a mythical
man-eating bird by the first

Polynesian settlers who arrived
here some 1,500 years ago.

And they came to places
like Hawaii

to try to set up
agricultural settlements.

Squares like this are common
for dividing up farmland.

Could it be
agricultural plots?

NARRATOR: Yet when Adam Ruben
reviews local land records,

he discovers the strange lines
don't appear until the 1930s.

This was a time when Hawaii
was particularly concerned

about the build-up
to a second World War.

So this coincidence of timing
indicates that maybe

the lines have something
to do with the war.

NARRATOR: The records confirm
that the satellite has captured

a bizarre relic of

one man's attempt to repel
the might of the Japanese

Imperial Navy.

A local ranch owner decided
that instead of waiting for

a Japanese invasion,

he would take matters
into his own hands.

CAVELL: It's kind of amazing.

I mean, he was protecting
an entire island,

and maybe even an island chain,
from a potential attack.

NARRATOR:
The story of the strange ruts

begins in the aftermath of
World War I, when the League

of Nations grants Japan
territories in the Pacific.

That puts the empire of Japan
sort of on a collision course

with the United States,

because the United States
is also occupying parts of

the Pacific, and the two
countries are beginning to

rival one another.

NARRATOR: In 1930s, Japan begins
a period of rapid military

expansion, which will see it

take over parts of China
and the Soviet Union.

With more than 40 percent of its
population of Japanese descent,

Hawaii is directly in

the firing line of
these Imperialist ambitions.

The Japanese looked toward
the Hawaiian islands as being

a place where they could
potentially establish

an overseas empire.

People on the islands are
certainly feeling the impact

of this increased tension.

NARRATOR:
Yet few in the U.S.,

including President Roosevelt,
believe the Japanese

possess the military strength
needed to threaten U.S. soil.

There is a lot of
thinking among,

especially naval planners,
that there

is no way that Hawaii would be
directly vulnerable

to an attack.

MORGAN: Most people were sort of
content to ignore the Pacific.

It didn't show up
in the headlines.

It was a third page matter.

NARRATOR:
Despite Washington's apparent

rejection of the Japanese,
threat among the Hawaiians,

fear continues to grow.

HYMEL: Everyone in the Hawaiian
islands is concerned,

but it's the island of Ni'ihau,

the most northern western
island, where the fear is

the most intense.

It would be the first
line of defense

in any kind of an attack.

NARRATOR: In 1933,
a local landowner identifies

the lake bed in the image as

a potential natural runway for
a Japanese invasion

and decides to act.

What he decided to do
was dig up

acres and acres and create

this grid system of trenches

that would prevent
the dry lake beds from becoming

the perfect landing strip for
Japanese aircraft.

HYMEL: If a Japanese plane
tries to land,

it's gonna hit these furrows
and either crack up on

landing or maybe even
flip over and pancake,

as the pilots call it.

NARRATOR: A small team of
Islanders uses shovels

and a plow to carve out

half a square mile of
2-foot-deep deep ruts

across the lake bed,
revealed from space.

Rutting up these lake beds is
no small undertaking.

It's going to take some
back-breaking manual labor.

Some people might have looked
at him as crazy,

but there really is a pretty
impressive foresight that he

sees the coming war

and creates this defense
that will deny

the Japanese any idea of using
this as a forward base.

NARRATOR: On December 7, 1941,
the maverick rancher's fears

are realized when 360 Japanese
aircraft rain down

terror on Pearl Harbor.

[explosion blasts]

[gunfire]

NARRATOR: In the aftermath,
a damaged Mitsubishi Zero

heads for Ni'ihau,

how hoping to land in the lake
bed in the image.

His plan is to put his
aircraft down and then rejoin

the fleet -- well, his plans
are gonna be foiled

by the trenches.

NARRATOR: The rutted lake bed
forces the pilot to crash land,

and he is detained by
the islanders,

one of the only Japanese
prisoners captured

during the infamous assault
on Pearl Harbor.

It really is kind of
a remarkable end

to a really dramatic tale.

MORGAN: And that's why the ruts
are in the lake.

And those ruts
can still be seen

to this day,
almost 80 years later.

NARRATOR: Coming up,
America's toxic time bomb.

This is a very dangerous
situation here.

NARRATOR: More than 150
Earth observation satellites

orbit our planet,

mapping its ever-changing
surface in

extraordinary detail.

KOUROUNIS: One great thing about
satellite imagery is that

we can look at pictures

from different periods of time
and see how

the Earth's surface
has changed.

NARRATOR:
A series of these images taken

over Green Township,
Pennsylvania, uncover a mystery.

There's something really
unusual about this lake.

RUBEN: Looking across time,
this body of water,

it's growing and shrinking.

It's changing shape,
it's changing color.

It's almost as if
it's a creature

living out its life cycle.

NARRATOR: What's more,
analysis reveals the lake's

morphing waters are forcing
those living nearby to flee

their homes.

If we look around
this lagoon,

we don't really
see signs of life.

The buildings look abandoned.

PATEL: It's a bit eerie.

It kind of makes you wonder if
there's something unsafe here.

NARRATOR: Samples taken from
the mutating lake

confirm that its waters are
highly toxic.

It's a cocktail
of arsenic and mercury

and lead, things that can
really harm human health.

This water is basically
a poison stew.

NARRATOR: The roll call of
deadly metals offers a clue

to the lake's origin.

We can trace the toxic
minerals that are coming from

this particular pond to

the waste products
from a power plant,

something called coal ash.

NARRATOR: Coal ash is a highly
noxious waste, created when

power plants incinerate vast
amounts of the fossil fuel.

And the two states
bordering the lake produce

over 20 million tons of
the stuff each year.

Whenever you burn coal
to generate power,

that coal combusts, and what's
left behind is a mixture of

various impurities
and chemicals that basically

have to be stored somewhere.

LESTER: Typically, it is
dissolved or mixed with water

and disposed of
in holding ponds or lakes.

NARRATOR: Back in 1974,

authorities tell
locals they are creating

a boating lake
at the site in the image.

Over the next 40 years,

they fill it with 20 billion
gallons of noxious

coal ash slurry.

Chemicals in the effluent
generate colors

so vivid,
they are visible from space.

It completely makes sense,

now, understanding
what's in this lagoon,

that these buildings
are abandoned.

The substances in coal ash
can cause all kinds

of problems,
and it has absolutely

devastated the community.

NARRATOR: Over the years,
the lake in the image grows

to become the biggest waste
dump in the U.S.,

and it's just one part of

an unfolding disaster that
could threaten

millions of lives.

These coal ash ponds are
a big problem across the U.S.

RUBEN: There are more than
a thousand of these sites

around the country,
many of them built

without the necessary
safety standards.

♪

NARRATOR: The coal ash
catastrophe engulfing America

is a legacy of
the country's extraordinary

industrial growth over
the past two centuries.

Between 1840 and 2010,
the U.S. population increases

from some 17 million
to over 300 million.

During the same period,
coal production surges from

2.5 million tons per year
to over one billion.

RUBEN: In many ways,
coal is a double-edged sword.

It has enabled
the Industrial Revolution.

Coal fueled America
for a long time.

But coal has consequences.

NARRATOR: Today, energy
companies dispose of 140 million

tons of coal ash each year,

enough to fill a line of train
cars stretching

halfway around the world.

More than 95 percent
of dump sites are unlined,

and over 200 ash lakes have

contaminated local water
supplies with

deadly pollutants.

Cancer, your lungs,
kidneys, heart --

all of those things can
be damaged

by exposure to these kind of
toxic minerals.

This is a very dangerous
situation here.

KOUROUNIS: These disposal sites
are a real problem,

and the thing
that bothers me is

there's almost no federal
regulation of them.

NARRATOR: Aerial images
reveal how this lack

of regulation can have
catastrophic consequences.

In 2008,
an ash pond levy

in Kingston,
Tennessee, collapses,

flooding a nearby town with
over a billion gallons of

contaminated sludge.

It's the largest industrial
disaster in U.S. history,

releasing five times as
much toxic

material as
the Deepwater Horizon oil spill.

It is just an awful tragedy

that has befallen
the community here.

Unless we start
to take into account

that these things
are dangerous,

we're gonna continue to see
lots of deaths,

lots of health problems
in general,

by the people living next to
these coal ash ponds.

NARRATOR: In 2016,
authorities begin to

clean up the site in the image,

but elsewhere, around six
million American lives

live within the deadly shadow
of ash ponds,

and for many,
time is running out.

RUBEN: We need power to run
this country,

and we need reservoirs to
create that power,

and that's all well and good
until it's your town

that ends up at
the bottom of a lake.