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.

Near Area 51,

the mystery desert mega weapon.

ALBERTSON: This is a reminder that some

powers are wielded at humankind's own peril.

NARRATOR: The horrors of Dead Man's Island.

They've seen hundreds of bodies just laying on the beach.

ZAHN: And Louisiana's cannibal swamp.

It looks like there's some giant monster

who's just sucking down entire sections of forest.

NARRATOR: Baffling phenomena, mysteries from space.

What on Earth are they?

**

**

**

Nye County, Nevada,

18,000 square miles of sand, scrub,

and not much else.

Trevor Albertson is journeying into these desolate

lands to investigate a mystery revealed from space.

There's nothing out here.

I mean, nothing.

Then you see this.

NARRATOR: This image, taken in July 2015, has uncovered

something strange in this empty desert.

JANULIS: You can see a series of

concentric circles and a sort of bull's-eye

in the middle.

MORAN: This is massive.

It would have taken quite some time

to build this or to create this.

MUNOZ: It looks like it's been abandoned,

but there's no telling for how long and what it was used for

before everyone left.

NARRATOR: Albertson believes the 20-million-square-foot

patterns are evidence of clandestine military activity.

But that's not all that

intrigues the former intelligence officer.

What's really interesting about this is the nearest base

is Groom Lake test facility,

which is more commonly known as Area 51.

The fact that this is near Area 51, of course,

raises all kinds of red flags and questions.

NARRATOR: Area 51,

a facility so secret that its existence

was only officially acknowledged in 2013

and whose workers commute to

and from the site in unmarked private planes.

This is where the government tests their most

secretive projects throughout the Cold War,

things that the government doesn't talk about or admit to.

There is a possibility this could be associated with that.

NARRATOR: Reports of strange experiments in these deserts

date back to the 1950s.

During this decade,

the U.S. military begins using the Groom Lake runways to

launch a series of incredible new experimental aircraft

known as X-planes.

But much of what else has taken place there

remains classified.

Groom Lake was the test facility

for its most secretive projects,

things that they didn't want the Soviet Union or other

powers to know about.

NARRATOR: Since the Cold War, Area 51 has continued to expand.

Area 52 is rumored to conceal

an underground base big enough to hold 25,000 soldiers.

And reports persist of strange experiments

in these remote desert valleys.

Looking around here,

it becomes readily apparent

it's the perfect place for

a secretive military or government test.

NARRATOR: If this was a secret test site of some kind,

the image suggests a lot of effort

has been made to erase evidence of it.

Whoa! Check this out.

We're out in the middle of nowhere here,

and now I got cables coming out of the ground.

Clearly, somebody is trying to

gather data out here about something.

That is curious.

That is really strange.

NARRATOR: From ground level, it's impossible to make out

many of the patterns revealed from the skies.

But there is something weird that wasn't visible

in the image.

ALBERTSON: What on Earth is that?

We're out in the middle of nowhere, desert for miles,

and right there, some kind of steel tube.

NARRATOR: The metal monolith sits dead in

the center of the site in the image.

ALBERTSON: It's very, very mysterious.

I can clearly see that this is sunk into the ground.

How far, there's no way of telling.

I'm gonna fire up the drone.

Let's get a look and see what's inside this thing.

[beeping noise]

Here we go.

[Albertson laughs]

I actually see nothing, because

the cylinder is filled with concrete.

I'm in the middle of the central Nevada desert.

There's nothing out here except this giant tube

filled with concrete.

NARRATOR: Albertson can only think of one reason

why the military would put this here.

Concrete means you're either trying to

keep something out or something in,

and something you might want to keep in is radiation.

This whole thing just got a whole lot spookier,

because that means I'm standing on

top of an underground nuclear test.

NARRATOR: During the Cold War, Nevada

was ground zero for the U.S. military's nuclear test program.

[explosion blasts]

Hundreds of explosions with a combined yield of more

than 85,000 tons

of TNT rock the desert and release untold amounts of

radiation into the skies.

They would bore out these holes,

sink them over 3,000 feet deep in many cases,

and detonate a nuclear weapon.

I mean, this is a real piece

of history we're looking at right now.

NARRATOR: But to Albertson, something doesn't stack up.

The official Nevada nuclear test site

is 100 miles away from here.

This makes no sense at all.

I don't know why anyone would want to come here.

There's no good reason for it.

This indicates something was different about this test,

and I'm really curious as to what that was.

What was different that forced them to do this here, this time?

NARRATOR: Coming up, the billionaire, the bribe,

and the one megaton nuclear bomb.

This is just too suspicious not to ask questions.

NARRATOR: And massacre of the Norsemen.

Could this be a long-lost Viking ship

and some of its crew entombed in the mud?

NARRATOR: In Nevada, Trevor Albertson

is investigating a secret government test site.

Something big happened here, something very big.

NARRATOR: A steel monolith penetrates its center.

It's clearly going into the ground, and I think this

is the chamber for the test of a nuclear weapon.

NARRATOR: At some point in the past,

an apocalyptically powerful weapon was detonated

under these sands.

But this is civilian land, far away

from the official Nevada test site.

ALBERTSON: I want to know more about this.

I mean, this is just too suspicious not to

ask questions.

**

Hey, it's Trevor. How are you?

NARRATOR: Albertson's old agency contacts provide a lead.

All right. I'll give him a call. Bye.

Jerry Rossi was a radiation expert at the site back

in 1968.

I was there the morning they set the device off.

What do you remember from that experience?

The device is brought in under cover,

and then they start lowering it down the hole.

That's when they bring on radiation safety crews

like mine.

NARRATOR: Rossi reveals that the patterns in the image are

the legacy of a bomb

almost 70 times more powerful than the one that

destroyed Hiroshima.

ALBERTSON: Jeez, one megaton, man.

-That's insane. -Yes, yes, it was.

And it was all hush-hush, top-secret.

But what I don't understand is that we are miles and miles,

over 100 miles, from the nuclear test site down in

southern Nevada -- I don't get it.

NARRATOR: According to Rossi, the bomb's

extraordinary journey to this remote patch of desert begins

in Las Vegas during the 1950s.

What can you tell me about Vegas during that era?

Las Vegas was Wild West, and, oh, man,

it was a crazy, crazy time.

It was unbelievable.

In the '50s, many of Sin City's

hotels were funded by organized crime,

and the mobsters soon realized that they could make

big money from the explosions lighting up the Nevada skies.

[explosion blasts]

MORGAN: It leads to the ultra-weird reality

of this spectator sport

of people gathering in Vegas to watch nuclear tests.

ANNOUNCER: ...Minus one minute.

Put on your goggles.

JANULIS: Imagine sipping a martini,

watching a mushroom cloud. That's insane.

NARRATOR: Tourists keep flocking to watch the nukes

until 1963,

when the Limited Test Ban Treaty puts a halt to

atmospheric explosions.

Tests are forced underground...

[explosion blasts]

...shaking the Vegas casinos till their chips rattle.

JANULIS: Aside from a normal, everyday people,

you had one really influential person complaining

about the explosions.

That was reclusive billionaire, Howard Hughes.

CAVELL: And when Howard Hughes got upset about

nuclear testing, something was bound to happen.

NARRATOR: By this point in his life, the playboy movie mogul

and aviation pioneer had become a recluse,

refusing to leave his penthouse on the Vegas Strip

for two years.

JANULIS: Despite that, he still had a lot of influence.

So he goes right to the top --

Lyndon Johnson -- he writes

a letter directly to the president, demanding

he stopped the nuclear testing outside Vegas.

NARRATOR: Rumors persist that the eccentric billionaire also

offers President Johnson a $1 million dollar sweetener.

Whatever the truth, on January 19, 1968,

Jerry Rossi and his colleagues find themselves 180 miles from

Hughes's penthouse, preparing to

lower a nuclear bomb into the desert floor.

ROSSI: We weren't supposed to say anything to anybody,

and if anybody asks,

we were working on drilling a well.

NARRATOR: In reality, the military wants to see whether

seismic instruments can be used

to spy on other countries' nuclear test programs.

The experiment is code-named Project Faultless.

The idea is that if we can take a seismic measure

of this nuclear explosion,

we can then monitor other countries and see if they're

testing nuclear weapons, as well.

NARRATOR: At 10:15 a.m.,

the bomb detonates

[explosion blasts]

Massive shock waves from the blasts radiate outwards,

shattering windows 87 miles away and heaving

40,000 square feet of desert into the air.

[explosion blasts]

Did anyone expect it to be this big?

It was far greater than they had ever imagined.

You know, I had to go home and change my underwear.

Everybody did.

NARRATOR: Yet what truly terrifies

the scientists is what's happening underground.

The blast activates two fault lines, which rupture the surface

for 3,400 feet

and create a colossal underground chasm known as

a nuclear chimney.

Scientists and engineers were so horrified by the effects

of the blast that they ended up canceling Project Faultless.

They capped the tube and carried out no

other experiments.

So clearly, Project Faultless is probably one of

the worst-named tests in history,

because it left behind it

a huge debris field of toxic waste that's deep underground.

NARRATOR: Even today, half a million tons of

atomic rubble remain, hidden beneath these sands,

with radiation levels similar to that of a nuclear reactor.

And while Rossi and his fellow scientists are long gone,

evidence of their extraordinary experiment

remains, visible from space.

You know, this is a reminder that

some powers are wielded at humankind's own peril.

And this will stand as

a reminder of that for centuries to come.

NARRATOR: Coming up, the ghost ships of Dead Man's Island,

They were horrific places,

very, very hellish indeed.

NARRATOR: And New York's $2 billion dollar time machine.

The discoveries being made there

are making history every day.

NARRATOR: August 7, 2020.

A satellite scanning a riverbank east of

London captures a strangely patterned island.

And emerging from its sands, a mystery shape.

HUNT: Smack in the main watercourse

is a gigantic imprint of a boat.

And it's not just any boat.

This is a big ship.

WALTERS: It looks like it's fossilized or something.

It's been there for a very, very long time.

NARRATOR: What intrigues analysts is that the island

the wreck sits on is strictly off limits to visitors.

Footage taken by the few who dare visit

the mystery wreck reveals why.

They have seen dozens, if not hundreds,

of bodies in the form of old bones just laying on the beach.

The locals call this place Dead Man's Island.

It's like a mass grave sitting right next to London.

NARRATOR: London's Thames River has a history stretching back

some 10,000 years,

and its waters have claimed countless ships and lives.

Accounts from 9th century monks provide a clue

to the carnage discovered on Dead Man's Island.

We know that Vikings invaded

this particular part of the coast,

so could this be a long-lost Viking ship

and some of its crew entombed in the mud?

NARRATOR: The monks' chronicles describe how, in 835 A.D.,

Norse warriors sail into

the Thames estuary in search of plunder.

HUNT: In the Viking period,

London is a magnet, because it's a huge, rich trading port.

They're interested in acquiring the luxuries that

were contained in the monasteries,

but also were seeking out slaves.

[voices clamoring]

NARRATOR: Due to a shortage of women in Scandinavia,

the Vikings kidnapped thousands of slave wives,

slaying their menfolk and burning their homes

to the ground.

In 1894 A.D.,

close to the site in the image,

the English reek a bloody revenge on their

Norse invaders at the battle of Benfleet.

HUNT: Benfleet is just across the river, and there was

a huge loss of Viking wealth, ships, and life.

HORTON: So it's possible these remains might

be associated with these skirmishes

between the Vikings and the Saxons.

NARRATOR: But the latest footage of the bodies buried on

Dead Man's Island doesn't fit with the Viking

massacre theory.

Looking closer, you can actually see wooden coffins.

So if someone took time to bury these bodies,

that does not look like the site of a battle.

NARRATOR: If not the Vikings, then who?

18th-century maritime records shed more light on

the origin of the wreck and the bones nearby.

From the research, what we find out is that this part of

the Thames estuary was actually used as a mooring area

for prison hulks.

NARRATOR: The ship is named the Justicia,

one of several floating prisons

once anchored off Dead Man's Island.

They were used to house inmates in some of the grimmest

conditions imaginable.

WALTERS: They were horrific places,

very, very hellish indeed.

You would not want to be on a prison hulk.

You better believe it.

NARRATOR: The story of Britain's floating horror jails begins

during the sweeping prison reforms of the 1600s.

MORGAN: In the late 17th century,

the prisons are overcrowded, and they come up

with a new penalty, and that's transportation,

and that means that the convict, instead of serving

time in prison in England, is

sent to the colonies in North America.

NARRATOR: Over the following decades,

the policy of convict transportation accounts for

a quarter of all North American immigrants.

CADDICK-ADAMS: Tens of thousands

make that uncertain journey across the North Atlantic

and find themselves as

the forefathers of today's United States.

NARRATOR: In 1775,

when war breaks out between the two countries,

Britain is forced to find another way to deal with

prison overcrowding.

The solution comes in the following year,

in 1776, when Parliament passes the Hulks Act.

NARRATOR: The Hulks Act leads to old, decommissioned

ships being converted into privately run floating prisons.

MORGAN: There are no rules that govern these ships.

They're run by contractors, and the more prisoners

they accommodate, the more money they make.

[clanking noise]

NARRATOR: Unscrupulous contractors cram 600 inmates

into ships designed to hold just 80.

A crime as minor as stealing a loaf of bread

could see you thrown into a cage

with rapists and murderers for 14 years.

MORGAN: These things are a living hell.

They're dark, they're dank, they're cold,

they're disease-ridden.

There are rats everywhere.

Typhus, cholera, dysentery, diphtheria.

You know, it's no surprise that the mortality

rate on these prison hulks was absolutely rocketing.

[sneezes]

Sickened, dying prisoners are often forced to bunk with

the dead -- it's the most disgusting place on Earth.

NARRATOR: Disease and mistreatment

kill up to a third of all prisoners -- on one ship,

typhus from a single inmate spreads to claim 176 lives.

[coughing]

WALTERS: What happens if you die on board of prison hulk?

You would be naive to suppose you're going to get buried

with your loved ones around you,

waving you goodbye.

What happens is you get dragged off board, your body

dumped into a very rough and ready coffin,

and that coffin is then just dumped near the boat.

NARRATOR: The convicts' bodies are swallowed by the marshes.

Today, they are slowly emerging from their muddy graves,

next to the very ship that

claimed their lives all those years ago.

MORGAN: What we're seeing here are the final remnants of a dark

chapter in British legal history,

where prisoners were held under the most

inhumane conditions.

NARRATOR: Coming up, inflatable Nazi killing machines.

MUNOZ: These became vital for any threats

coming across the Atlantic.

NARRATOR: And whale apocalypse.

This is a catastrophe that we're witnessing.

NARRATOR: August 2019.

As a satellite passes over the tip of Long Island, New York,

it spots something partially concealed in the woods below.

MORAN: This is a really strange image.

It's this enormous, perfectly circular

structure that

looks almost like an ancient henge or something.

NARRATOR: The mystery structure's location

offers a clue.

Long Island has a long history intertwined with the military.

So I wonder if there could be some explanation there.

The overgrown quality suggests that this is an old,

maybe abandoned facility,

maybe even dating back to the Second World War.

NARRATOR: Declassified World War II images

reveal other similar structures

along this stretch of coast.

WALTERS: What this strongly reminds me of,

and what I suspect it is,

is a landing area for an airship.

NARRATOR: The wartime airship stations

form part of a revolutionary program

to help America defend itself against the Nazi menace.

WALTERS: America was always a big pioneer of using balloons

for military applications.

I mean, they were even used in the American Civil War.

[shouting]

NARRATOR: The Union Army balloons lift aeronauts

1,000 feet into the sky,

providing them with a 15-mile view across the battlefield.

MORGAN: That's more than a day's march.

So a balloon could function as

a very effective advanced early warning system.

NARRATOR: To enrage the Confederates,

many balloons carried portraits of Union Army generals.

MORGAN: The balloons were brightly painted,

so they weren't trying to hide,

they weren't going for stealth.

MORAN: They were somewhat conspicuous

and could very well become cannon fodder.

NARRATOR: As World War II looms, military balloons are

resurrected to deal with a much deadlier threat than

Confederate artillery.

PAVELEC: During the Second World War,

lighter-than-air dirigibles and blimps will watch for

and protect against German submarines in the Atlantic.

NARRATOR: As the war unfolds, U-boats present

a massive danger to vital American supplies

crossing the Atlantic.

With millions of tons of cargo being lost,

the Navy dispatches 150 airships to

conduct anti-submarine missions out at sea.

MUNOZ: These U.S. airships really became a vital

lifeline for the U.S. Navy

in terms of providing early warning of

any threats that could be coming across the Atlantic.

MORAN: The United States ended up building over half

a dozen of these stations all along the coastline.

So could what we're seeing be

a station that once housed a military blimp?

NARRATOR: Planetary scientist Pascal Lee studies the image.

He believes that the structure does have its origins in

the 1940s,

but wasn't built to help in the fight against Hitler.

LEE: What we're seeing here is not a military facility,

but a fundamental physics research laboratory

where we're learning about the intimate

behavior of matter in the universe.

NARRATOR: This is the Brookhaven National

Laboratory, which opened in 1947.

Over the years,

the work conducted here has ranged from

research that has won seven Nobel Prizes,

to pioneering the first video games.

Today, the circular structure in the image is

on the hunt for an even bigger trophy.

LEE: The circle here in the middle

is their relativistic heavy ion collider.

It's a particle accelerator where we can study

the makeup of particles at the very beginning of

our universe.

NARRATOR: 13.8 billion years ago,

everything we observe in the universe -- stars,

nebula, black holes -- was packed into a single point.

A sudden event, the so-called Big Bang,

then spawned all matter in the cosmos,

one so cataclysmically powerful that even today,

the universe continues to expand at an astonishing rate.

What the state of matter was at the time was this very hot,

dense gas, if you will,

made up of individual particles, which eventually,

once they cool down, gave rise to protons and neutrons

and the other things we're familiar with.

NARRATOR: The collider in the image

helps scientists understand the birth of the universe by

mimicking the aftermath of the Big Bang.

Inside, 1,740 superconducting magnets,

accelerate ions to close to the speed of light.

When they collide, they create temperatures

of around 7.2 trillion degrees Fahrenheit,

250,000 times hotter than the core of the sun.

When you collide, the energy that is exchanged is so...

monumental that you can actually break up

even the most tightly bound particles and really see what

matter is made up of.

NARRATOR: By studying this primordial soup of particles,

scientists hope to decode the blueprint

of how the cosmos is constructed.

MORGAN: What we're actually looking at here is one of

the most important research laboratories

in the entire world, where the discoveries being made

there are making history every day.

NARRATOR: In effect, the structure in the image

is a time travel machine,

one that may one day help us

solve perhaps the greatest mystery in science.

LEE: Who would have thought that we are essentially recreating

the early moments of our universe

on Long Island, New York?

**

NARRATOR: Coming up, what's killing nature's giants?

Something is causing hundreds upon hundreds of whales to die.

NARRATOR: And the swamp that ate itself.

Whatever is happening here

is basically eating up the whole surrounding.

NARRATOR: September 21, 2020,

Tasmania,

150 miles south of mainland Australia.

A helicopter scans beaches on the west of the island.

Passing over Macquarie Harbour,

the on-board camera captures

disturbing images of the waters below.

There's something funny here.

There's these little specks along the coastline,

just kind of, like, dotting it.

When you zoom closer, you can

start to see that they're actually moving.

NARRATOR: Hundreds of pilot whales have beached themselves,

and they are fighting for their lives.

They're sick, they're dying.

This is a catastrophe that we're witnessing.

NARRATOR: This is the largest mass stranding in

Australian history.

Within hours, rescuers arrive at the scene,

They were able to save 90, which is great.

But that still meant that almost 400

animals died on the beach that day.

NARRATOR: What's more, this is the 30th mass pilot whale

death on the island in the last three decades.

What's really unfortunate is this situation isn't unique.

Something is causing hundreds upon hundreds of whales to die.

NARRATOR: The cause of these tragedies

continues to baffle biologists.

When news of the latest one spreads,

some observers identify a possible culprit.

KAYS: There's a lot of concern that military

sonar could have really bad effects on whales.

And there are companies near where these whales

stranded that are developing these types of technologies.

NARRATOR: The military tests are trying to replicate

one of the whales' most extraordinary abilities.

Pilot whales have this rounded forehead that's actually called

the melon, and that is where they send out their

echolocation calls.

NARRATOR: Like sonar, whales use echolocation by bouncing sound

waves off nearby objects -- by focusing the echoes,

they can pinpoint prey the size of

a golf ball in the dark ocean depths.

But as our oceans become more militarized,

they're becoming very, very noisy.

And when you're a whale that depends on your sense

of hearing, that becomes a really big issue.

[high-pitched whale call]

NARRATOR: The details of the Australian sonar tests

are classified,

but similar experiments involve using underwater

speakers to pump out pulses

of sound that can exceed 230 decibels.

To put this into perspective, the human

ear drum shatters around 140 or 160 decibels.

That is literally ear-splitting sounds

being broadcasting.

[high-pitched whale call]

NARRATOR: The fear is that these noises stun the whales,

forcing them into shallow waters.

KAYS: We don't know if there were underwater sonar tests

going on at the moment of this beaching,

but it seems like that is one of the possibilities of

the causes of this mass whale stranding in Tasmania.

NARRATOR: But other scientists speculate that freak

natural phenomenon could instead be to blame.

When we measure the magnetic field of Earth,

we can see that there's an unusually weak circular area

in this part of southern

Australia called the Coompana Anomaly.

SCHUTTLER: Given that whales use the Earth's magnetic field

to navigate,

maybe it's confusing the whales,

messing up their navigation system.

NARRATOR: The Coompana Anomaly was first

discovered when planes flying

over southern Australia reported strange things

happening to their instruments.

It has this weird, crater-like shape.

Some scientists think it might be

the result of an ancient meteor impact.

DENNIE: We don't really know for sure what causes it,

but something about the geology in this area is causing

a magnetic field that's weaker in all the areas surrounding it.

NARRATOR: Magnetic anomalies are known

to play havoc with spacecraft,

even sending them spiraling out of control.

In whales, they could interfere with a mysterious 6th sense,

which enables them to

use the Earth's magnetic fields to navigate millions of

square miles of empty ocean.

Magnetoreception is like a superpower,

but it's a superpower that's still quite a mystery.

[high-pitched whale calling]

It's possible that if there were shifts in

the electromagnetic fields,

it could cause a major disruption

to how they could navigate.

[high-pitched whale calling]

NARRATOR: Some scientists agree that magnetic disturbances

are to blame for the whale deaths,

but ones originating from a very different source.

KAYS: When the sun goes into a period of high activity,

we see big waves of electromagnetic radiation

hitting the Earth.

Researchers have found that if you plot the solar activity

with the times that we see a lot of whale strandings,

it explains some of these terrible stranding events.

NARRATOR: Solar flares release 10 million times more energy

than a volcano and can knock out entire power grids.

A particularly powerful solar eruption could fry the whales'

ability to detect variations in the earth's magnetic field.

It's kind of like if you're driving in a snowstorm,

you're more likely to get into a car accident.

If you have a solar storm, and you're relying on magnetic

reception to navigate,

you're more likely to make a navigational error.

NARRATOR: Scientists continue to search

for answers to explain

the increasing number of whale deaths reported worldwide,

and time is running out.

Nobody really understands why, but it's happening

more and more often.

The whales are dying in massive numbers.

It's a tragedy and a biological mystery to boot.

NARRATOR: Coming up, Louisiana's killer abyss.

It was a devastating disaster,

and it looks like history may be repeating itself here.

NARRATOR: August 2, 2012.

Eyes in the sky scan a forested area of

Louisiana, some 35 miles inland from the Gulf of Mexico.

This image looks like any normal swamp

that you would see in southern Louisiana.

You see roads and greenery, rivers, the usual.

NARRATOR: But as the camera passes over

the same patch of swamp just 24 hours later,

it captures something weird.

All of a sudden, there's this hole,

like something swallowed the swamp right up.

Literally from one day to the next,

there is this dark patch coming out of nowhere.

NARRATOR: Footage taken at ground level reveals

that the swamp has turned cannibal.

It looks like there's some giant monster lurking at

the bottom of the water

who's just sucking down entire sections of forest.

NARRATOR: Over the following weeks,

the swamp-swallowing vortex continues to grow,

forcing residents of the nearby town to flee

their homes.

If I lived in this town, it would be terrifying.

Whatever is happening here is

basically eating up the whole surroundings.

NARRATOR: Eyewitness accounts from the days leading up

to the event offer the first clues.

RUBEN: Local residents say that when the hole first appeared,

the ground under their houses started to shake.

Not only that, but frequent tremors were reported

in the two months before the sinkhole opened.

NARRATOR: What puzzles analysts is that seismological

data shows no evidence of any earthquakes.

It suggests some other freak

geological phenomenon is to blame.

It's possible that the unique geology of Louisiana can

give us some clues as to what's going on.

NARRATOR: What's unusual about Louisiana is that it sits

on top of giant mineral deposits called salt domes.

In some cases, these salt domes

can be as tall as Mount Everest.

So there's a tremendous amount of salt beneath your feet.

In Louisiana, there are 100 huge salt domes

sitting under the surface of the Earth.

And looking at the map,

we see that some of them are right in this spot.

NARRATOR: Louisiana's salt domes are the remains of a shallow

ocean that covered the state 300 million years ago.

When the waters evaporated,

they left behind vast salt flats, which were swallowed by

the Earth.

Salt has a lower density than the surrounding rock.

And so the pressure around it can

push it up into these, like, dome-like structures.

And the closer the salt dome comes to the surface,

the more easily we can mine it for food and industry.

[explosion blasts]

NARRATOR: They've been mining Louisiana's salt domes since

the Civil War.

In the last few decades alone,

millions of tons of the mineral have been chiseled

from the earth.

SALAITA: We have to drill down sometimes to 10,000 feet

to get at the salt that's underneath the surface.

CERVENY: So as they've been mining this salt,

this area has become filled with lots of tunnels, and that

leads to instability over the whole area.

NARRATOR: These salt caverns are normally very stable,

but events in Louisiana four decades ago

show that things can go catastrophically wrong.

This happened in Lake Peigneur in 1980.

Workers were drilling for oil when the oil

drill became stuck in a salt dome under the water.

The drilling equipment and all of

the supporting equipment were sucked into a giant whirlpool.

It was a devastating disaster, and it

looks like history may be repeating itself here.

NARRATOR: An investigation confirms that

drilling was taking place in

the swamp prior to the sudden appearance of the giant hole.

This sinkhole is right next to

a mining operation that was set up

to extract salt-enriched waters,

which are called brines.

NARRATOR: As the brine is removed from the salt dome,

groundwater seeps in, creating a geological time bomb.

When that happens, it dissolves the salt dome itself.

You're left with an empty shell, and it will collapse.

NARRATOR: Three companies were prosecuted for

triggering the town-swallowing chasm,

but many in this state fear this won't be

the last time they see their lands

being swallowed by the swamp.

RUBEN: There are more than 120 salt domes just in Louisiana,

so who knows where or when the next sinkhole will open up.