All language subtitles for What.on.Earth.S10E03.1080p.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.

Terror stalks an
Arizona ghost town.

There were those
who believed he had

supernatural powers
and couldn't be shot.

NARRATOR:
The wrath of Genghis Khan.

Even to this day, it's known
as the City of Screams.

NARRATOR: And the miracle
waters of the New World.

This water gave them
protection against

terrifying diseases.

Baffling phenomena,
mysteries from space.

What on Earth are they?

[theme music playing]

NARRATOR: March 11th, 2021.

High over
the Arizona mountains,

a satellite captures
a strange structure

amongst the barren peaks.

This is a really
intriguing image, because this

is surrounded by thousands of
square miles of desert.

NARRATOR: Image analysis
suggests the structure

consists of vast pieces of stone
spread across 1,000 acres,

some at elevations
above 5,000 feet.

BELLINGER: Some don't even
have complete walls,

so whatever is here,
it's in ruins.

What's really striking about
this image is, geologically,

we're really high up.

NARRATOR: Drawn by the
unexplained alpine structure,

geologist Martin Pepper is
traveling into the mountains

to investigate.

Why would people haul all
this material way up here

into the hills?
It doesn't make sense.

NARRATOR: Beneath
these mountains are seams

of gold, silver, and copper.

Arizona is dotted with
crumbling mining towns,

but Pepper doesn't buy
this explanation.

Typically, these
settlements literally

exist right where
they're mining,

and so we would see big
tailings coming out of some of

these slopes,
but I'm not seeing that here.

NARRATOR: From space,
it's impossible to assess

the age of these structures,

but clues can lie
in the dirt.

Ah, look at this.

This is not recent.

That's old lead solder,

and so we're talking about
the 19th century.

NARRATOR: Ascending to the site
in the satellite image,

Pepper is prepared
for 19th-century ruins.

Check that out.

NARRATOR:
He's not prepared for this.

Jeez!
Look at the scale of this.

This is monumental.

NARRATOR: The satellite has
captured significant structures.

There's evidence of almost
40 buildings, heavily

fortified, with thousands of
tons of stacked stone.

Just the width of
these walls, you know,

2, 3 feet thick,

shows that whoever built this
wanted it fortified

and really strong.

Why would something
this big be

out here in the middle
of nowhere?

NARRATOR: The geologist
returns to the image

that lured him here.

Looking at this image,

zooming in over here,

I can see this green area.

NARRATOR:
Pepper heads west.

There it is.
Look at that.

Ah, and there's the spring
right up there.

NARRATOR: The spring
and 19th-century ruins

sit in perhaps

the only navigable route
between the Dos Cabezas

and Chiricahua Mountains.

PEPPER: These mountains block
what we have west to California,

so this must be some sort of
mountain pass.

NARRATOR: Via this
mountain pass, it's 400 miles

to the Golden State
of California,

the last leg in the most

treacherous migrant route
in U.S. history.

In the mid to late
19th century, California was

the destination for
fortune seekers,

but getting to California was
a very dangerous proposition.

[banjo music playing]

NARRATOR: Census records
show that between

1848 and the mid-1850s,

more than 300,000 people flood
into California,

lured by the promise of gold.

Wagon trains snake through
Arizona's mountain passes.

This water would have been
extremely valuable in one

of their stops off as they
headed towards the west.

NARRATOR: Disease, starvation,
and fatal accidents are common.

Tens of thousands failed to
finish a journey which averages

10 graves per mile.

Settlers had to literally run

the gauntlet to go
through these passes.

JANULIS: The Spanish name
for this pass is

Puerto del Dado,
Pass of the Die,

and that's not die
as in death,

but as in gambling dice.

Coming through here means
you're gambling with your life.

NARRATOR: One gambler
not prepared to lose

is New York businessman
John Butterfield.

Butterfield's stagecoach was
the first truly

transcontinental postal service

and it ran all the way
from St. Louis, Missouri,

to San Francisco.

NARRATOR: The massive migration
west triggers

a fresh challenge --
how to haul the U.S. mail

to California.

In 1857, Butterfield wins

America's largest ever land
mail contract --

2,800 miles, five times
the length of the U.K.,

through some of the most
treacherous terrain on Earth

in a stagecoach.

John Butterfield had
a statement

that really stood out --
"Remember boys,

"nothing on God's Green Earth
should stop the mail from

getting through."

NARRATOR: Butterfield
rounds up 200 coaches,

almost 2,000 horses and mules,
and hires 1,200 men.

To win the contract,

He's promised to complete
the route in 25 days,

leaving him no choice but to
navigate the Pass of the Die.

A small staging post was
established at the head of

the pass where

a postal rider would stop for
a rest before pressing all

the way on to California.

But a thousand-acre
fortified structure is

far more than a small
trading post.

PEPPER: Why would this fort be
so important

right here? There must
have been something

else leaving everybody
terrified of a possible attack.

NARRATOR: Coming up, mass
slaughter in the mountains.

This place has a long history
of bloodshed and unrest.

NARRATOR: And the lost swamp
people of South Carolina.

JANULIS: It was the first
attempt to settle the shores

of the New World,

and it was
an absolute disaster.

NARRATOR: Drawn by remote stone
ruins spotted from space...

Jeez, look at the scale of
this structure.

...geologist Martin Pepper
is high

in the barren mountains
of Arizona.

This is monumental.

NARRATOR: He believes these are
19th-century fortifications

overlooking a snaking
mountain pass,

the most treacherous migrant
and mail route in history.

It's in the perfect
strategic position to

protect anybody trying to
safely pass through here.

But protect them from what?

Pepper seeks answers
in the area around the ruins.

Look at this.

Looks like some sort of
a cemetery or something.

NARRATOR: The century-old
cemetery may hold

clues about the immense
mountain structure.

PEPPER: Colonel Stone,

John Slater,
killed by Apaches.

Killed by Indians in
the Apache pass.

This is literally right in
the middle of Apache territory.

NARRATOR:
The formidable Apache control

a 30,000-square-mile territory
around the site in

the satellite image.

After five centuries of peace,
they are drawn into war.

In the 1730s, the Apache
came into conflict with

the Spanish, who were seeking
to expand their landholdings

in Mexico.

Their raids against
the Spanish

were both savage
and calculated.

NARRATOR:
Between 1771 and 1776,

the Apaches slay
1,600 Spaniards

and steal 68,000 animals.

They were one of the first
groups to

fully adopt the horse
and become horseback warriors.

NARRATOR: Spanish horses
and guns empower the Apache.

[gun cocks]

Hardened by battles
and betrayal,

they defend
their land ferociously.

The Apache became so dangerous
that it was just

too difficult for people to
pass through the mountains.

Passage is vital for
the Butterfield Mail Company,

who, in 1858,

broker a truce with
Cochise, an Apache leader

renowned for his willingness
to embrace white settlers.

BELLINGER:
For a few years,

the Apache would allow
the postal workers

to go through
the pass unscathed.

HORTON: Indeed, they even
trade commodities

and so forth
with the stage coach.

NARRATOR:
It's an unrivaled armistice

sadly shattered

on February 3rd, 1861.

Lieutenant Bascom
of the U.S. Army

accuses Cochise
of kidnapping

an American child,
and in fact, he had not.

But this whole event is gonna

end in bloodshed
on both sides.

NARRATOR: Much of it at
the Battle of Apache Pass.

BELLINGER: The Apache were
prepared to fight,

and they had studied American
military tactics.

NARRATOR: In July 1862,
500 Apache warriors ambush

U.S. forces led by
Captain Thomas L. Roberts.

Roberts retreats to
the Butterfield Mail Depot

and readies his secret weapon,

two 12-pound mountain
howitzer cannons.

Nothing the Apache had
at their disposal could

compete with
the massive firepower

possessed by the Americans.

[cannons blasting]

The Apache would have been
terrified with these

howitzers that would literally
cut them to pieces.

NARRATOR: 63 Apache are slain
by howitzer shells.

The rest flee.

The battle is over.

The war has just begun.

CAVELL: What this event
triggers is 25 years of

warfare between the U.S. Army
and the Apache.

NARRATOR: In 1864,
to defend Apache Pass,

the U.S. military
establishes the structure

in the satellite image,
Fort Bowie.

Fort Bowie
will become Ground Zero to

try and deal with
this Apache menace.

This was an original window
that they then bricked up

and most likely it turned into

a rifle opening
to shield the shooter

in case of attackers.

[gunshot
and indistinct shouting]

NARRATOR: The war pits U.S.
generals against legendary

Apache tactician, Geronimo.

While Geronimo was hugely
important to the Apache nation,

he was never actually a chief.

He was known as a shaman.

There were those who
believed he had

supernatural powers
and couldn't be shot.

NARRATOR: Led by their
invincible shaman,

Geronimo's Apache
take advantage

of their local knowledge.

JANULIS: They used guerilla
warfare tactics,

which means hit and run,
retreat back to the mountains,

and then do it again.

ALBERTSON: There was really
no quarter on either side.

The United States Army
committed 5,000 of

the active duty army to
chasing down Geronimo.

NARRATOR: The war claimed tens
of thousands of casualties.

The fallen are buried in
desert graves

like those by the fort

in the satellite image.

Fletcher, 1880.

Unknown Apache child.

Another Apache child, 1885.

Oh, wow, son of
Geronimo himself.

Little Robe.

NARRATOR: In 1886,
Geronimo surrenders,

effectively ending
the Apache Wars.

After a quarter-century
of conflict,

friend and foe
rest side by side.

PEPPER: This showed that
they came to some sort of truce

to bury them right here
in the same cemetery.

NARRATOR: The ruins of
Fort Bowie and its cemetery

are reminders of all
who fell at Apache Pass

and a stark warning from
American history.

What we can see from space was
the beginning of the end,

before the Apache were broken
and put onto reservations.

And even though
it's peaceful and tranquil now,

this place has a long history
of bloodshed and unrest.

NARRATOR:
Coming up, killer seas.

Whatever has happened here,
it's not good.

NARRATOR: And red dawn.

These innocent-looking circles
are a key zone of the Cold War.

NARRATOR:
October 1st, 2020.

The Landsat 8
satellite scans

the U.S. Eastern
Seaboard captures

something bizarre
spreading from

South Carolina's coastline.

KOUROUNIS: This image is
absolutely shocking.

Typically, the waters
off of Winyah Bay,

South Carolina, would be
beautiful blue-green,

but it is stained brown.

SZULGIT:
This is no small plume.

Whatever is leaking
to the ocean is big.

NARRATOR: Something
in Winyah Bay estuary

is pumping millions of gallons

of rust-colored water
into the Atlantic Ocean.

I think it's safe to say that
whatever has happened here,

it's not good.

NARRATOR: Satellite images
taken over the Carolinas

two years earlier
could offer a clue.

In 2018, tremendous amounts of
rainfall caused flooding

that overflowed pig farms,

and there were literally
floods of pig manure

leaching out into
the nearby watersheds.

NARRATOR: North Carolina's
hog farms house

around nine million pigs,

which each pump out around
two tons of manure a year.

The 2018 floods create
fecal tsunamis

so large they can
be seen from space.

A flood of pig manure turned
the rivers brown, and it really

bears a striking resemblance
to what we're seeing

in this image here.

NARRATOR: Yet what puzzles
analysts is that there are

reports of similar plumes
dating back many centuries.

They are often
referred to as blackwater.

The long history of people
recording this blackwater

tell us that it predates
industrial pollution,

so that's probably not
the cause of it.

NARRATOR: What's more,
the historical reports claim

that the noxious-looking waters
possess strange

healing properties.

SZULGIT: They say that
drinking in and bathing in

this water actually helped
with their condition.

NARRATOR: The first accounts of
blackwater date

to as far back as 1526.

HORTON: A Spanish pioneer
settler called

Vazquez de Ayllon

arrived with over
500 fellow Spaniards,

and they planted a colony

close to the mouth of the river.

SZULGIT: When we think of
the difficult conditions

that early settlers faced,

we think of them freezing to
death in the winter

or having battles with
indigenous peoples.

But really, the most dangerous
thing they faced was disease.

NARRATOR: During the age
of discovery, disease is

the principal cause of death
among sailors and settlers.

Scurvy alone kills two million,
typhus, typhoid, and dysentery,

countless others.

Back then, sailors would have
been in these terribly septic,

horrible conditions
where disease would be rife by

the time they arrived
on their vessels.

NARRATOR: For the Spanish
settlers in 16th-century

South Carolina, locating a clean
water supply is critical,

but the state's
fetid waterways are

a petri dish of bugs
and possible infections.

Not only

does it provide contaminated
water sources,

but also becomes a breeding
ground for mosquito that can

spread diseases such as
malaria and dengue fever.

NARRATOR: Faced with
this onslaught

of waterborne horrors,

the Spaniards find sanctuary
in the blackwater

seen from space.

When we look at where
the water feeding into this

river comes from,
it's passing through

a lot of swamps
and wetlands,

so it's gonna be interacting
with a lot of

decaying plant matter,

and that's going to make it
pick up certain things.

NARRATOR:
As the rivers move through

forests and wetlands
towards the sea,

rotting plant matter
leeches tannins

and organic molecules called
phenols into the water.

All these natural compounds in
the water basically

make it self-sterilizing,

allowing it to be very safe
to drink.

NARRATOR: The healing properties
of blackwater helped

the South Carolina colonists

to establish the first
European settlement on

the continental United States,

but their stay is short-lived.

The minute this settlement
gets to shore,

everything goes wrong --
their supply ship grounds

and cuts off their means of
escape, their lifeline.

They rapidly run out of food
and resources, because they

don't know the landscape
and the colonists

start dying of starvation.

NARRATOR:
A month after their arrival,

the Spanish flee, and their
settlement is swallowed by

the swamp.

It was the first attempt
to settle the shores

of the New World, and it was
an absolute disaster.

NARRATOR: Five centuries later,
a hurricane hits the site of

the Spanish colony,

generating the giant plume of
blackwater captured

from the skies.

As it spreads
across the Atlantic,

it prevents sunlight from
penetrating the ocean,

leading to a mass die-off
in the depths below.

SZULGIT: It's ironic
that the dark water

that we see
in the satellite image

that would have been
a calling card

to early settlers
for health and invigoration

turned out to be death to
the oceans

hundreds of years later.

NARRATOR: Coming up,
setting fire to runways.

Hey, in wartime,
you're gonna

try pretty much anything
to be effective.

NARRATOR: And the city
that enraged Genghis Khan.

This was obviously
a very bad decision.

NARRATOR:
February 11th, 2020,

478 miles above
southwestern England,

a satellite captures
this image.

What you've got here is
an airfield,

that much is obvious.

But then when you look at it
a little bit more closely,

you realize there's something
very, very unusual indeed.

There's a bunch of circles
and also rectangles,

and what's interesting is
there's a great deal of

precision to the shape
and the placement of them.

NARRATOR:
Each of the mysteries shapes

is around 400 feet
in diameter.

It also looks like
there's no sign of life.

So if this was active, it must
have been decades ago.

NARRATOR: Analysts turned
to local land registry documents

for clues.

Looking at the records,
this is St. Eval,

an RAF coastal command station
from the Second World War,

very active from
1938 to 1945.

NARRATOR: The airbase is
one of 444 airfields

the British build
during World War II,

with enough combined
runway to stretch

from New York to Hong Kong.

PAVELEC: The base is
close to the coast,

so it was given the orders
of finding

and destroying German
submarines out in the water.

NARRATOR:
Over the course of the war,

hunter-killer aircraft from
the base helped destroy over

200 U-boats threatening

American lives
and Allied supplies.

Yet, as they return
from their missions,

many pilots encounter
an unexpected and deadly threat.

Basically, England's got
this dual problem of heavy fog

and then a lot
of industrial waste

coming up in clouds
from the factories,

and those two combined
and make almost, like,

a pea soup that pilots
could not see to land in.

NARRATOR: The clouds
of dense fog and smog,

which envelope wartime Britain,

claimed the lives
of numerous pilots.

They force Prime Minister
Winston Churchill

to develop
an extraordinary solution,

one that could explain
the weird shapes in the image.

WALTERS: What the scientists
come up with is

this ingenious idea,
and it's called FIDO.

Now, FIDO is not a big dog.

What FIDO stands for is

Fog Investigation and
Dispersal Operation.

The idea is to run pipes
on either side of the runway

and then flush them with fuel
that ignites, and so it

basically illuminates
the runway,

enabling the pilots
to land safely.

NARRATOR: The infernos
generated by burning

120,000 gallons of fuel
an hour

also help to disperse
thick fog above the runway.

PAVELEC: It seems a little
counterintuitive

to set fires along

the side of the runway
where you're trying to land,

but hey, in wartime,
you're gonna

try pretty much anything to
be effective.

NARRATOR:
Between 1943 and 1945,

the FIDO system saves
the lives

of 10,000 British
and American aircrews.

But closer analysis reveals
the mystery shapes

aren't connected to this fiery
flight safety system.

MUNOZ: If you zoom in,
and you look at

the center of these circles,

you see sort of
an antenna-type structure.

NARRATOR: Declassified
military files confirm

that these are
transmitter stations,

ones that played
a vital role in

events that unfolded after
World War II.

In the immediate aftermath
of the Second World War,

the United Kingdom was in
a very difficult position.

It had prevailed in
the victory,

but the economy was devastated.

NARRATOR: Britain's role in the
Allied victory in World War II

cost the nation around
$1 trillion

and leaves its industries
and defenses in ruins.

As the Cold War dawns,
this makes it highly

vulnerable to an attack from
its former ally, Russia.

There was a period of time
that we thought

that World War III
was going to begin in

Berlin and that it was going
to continue with an all-out

Soviet attack
on the United Kingdom.

[people shouting]

NARRATOR: Fearing a possible
communist invasion,

the U.S. dramatically ramps up
its military presence

in Britain,

including at an airbase to
the south of the site

in the image.

At any given time during
the Cold War, there would have

been thousands of U.S. troops,

and not just the troops,
but the aircraft

and the weapons capability

should there be
some kind of conflict.

NARRATOR:
Much like during World War II,

perhaps the greatest threat to
peace comes from submarines.

During the Cold War,
the Russians build around

1,450 subs
and have the largest,

most powerful fleet
in the world.

To track this menace,
the U.S.

and Britain turn to
the Hawker Siddeley Nimrod,

a passenger jet modified for

clandestine maritime
surveillance.

The Nimrod was
an incredibly interesting

aircraft -- essentially,

it was like
the Swiss army knife.

It could be equipped
with weapons,

torpedoes, or for intelligence,
surveillance,

and reconnaissance operations.

NARRATOR: With a range of
almost 6,000 miles,

Nimrods relentlessly comb
the ocean for Russian subs,

relaying critical surveillance
data back to the site

in the image.

Pilots are
authorized to deploy

B-57 tactical strike
nuclear depth bombs

on any intruders
into British waters.

If you look at it, you would
see basically a passenger jet,

but a passenger jet filled
with either high-powered

weaponry or very
sophisticated equipment.

NARRATOR:
During its 40-year lifespan,

the Nimrod flies countless
missions over hostile waters,

helping to repel
the Soviet threat.

Today, evidence of its vital
yet overlooked role at

the front line of the Cold War
remains, visible from space.

WALTERS: These
innocent-looking circles

are a really highly protected
key zone of the Cold War.

It's one of the most secure
places on Earth at the time.

NARRATOR: Coming up,
attack of the scourge of God.

If you resisted,
no mercy was shown.

NARRATOR: And
the $60 billion hoard.

If you're a treasure hunter,

you might want to get out
there now.

NARRATOR:
August 19th, 2018.

A satellite orbits the Sistan
Basin in southern Afghanistan,

140,000 square miles

of some of the most
inhospitable terrain on Earth.

KOUROUNIS: In every direction,
for hundreds of miles,

there's nothing but emptiness
and sand dunes.

NARRATOR: Yet closer analysis
reveals mysterious evidence of

human presence
in these inaccessible,

Taliban-controlled wastelands.

MORGAN:
There's a larger outer circle,

and then a smaller inner circle

with some structures inside
of it -- it looks enormous.

NARRATOR: The mystery crumbling
edifice covers

two million square feet
of desert.

There are no trees,
there's no water,

no other signs of habitation,

just this large structure
that obviously took a lot

of effort to build in
the middle of nowhere.

NARRATOR: Dialing up
the magnification reveals

the structure is defended
by a series of concentric

walls up to a mile long
and 30 feet thick.

Military expert Sam Cavell
studies them for clues.

The architecture here is very

reminiscent of Islamic
military fort design.

It looks like the kind of
structural elements

you would expect to see

in something that dates
to about the 13th century.

NARRATOR: It appears
the giant desert fort

was designed to defend against

the onslaught of perhaps one
of the most dreaded forces in

all human history.

In the 13th century,

one of the greatest threats to
this area would have been

the Mongol Empire,

led by one of the most
fearsome warriors of all time,

Genghis Khan.

NARRATOR: The Mongols' journey
to these deserts begins

in the Central Asian steppes
in 1206 A.D.

Mobilizing 100,000 highly
trained horseback warriors,

Genghis Khan sweeps west,
covering up to 100 miles a day,

conquering all in his path.

Over the next 160 years,
he and his descendants slaughter

up to 40 million people,

creating
a 12-million-square-mile empire

that stretches from
the Pacific in the east

to Poland in the West.

Mongolians were known
simply for barbarity.

They were known
for moving in and raping,

pillaging, and plundering
everything that they could get

their hands on.

1219 A.D., the Mongol Horde,

known as the Scourge of God,
reaches Afghanistan, ruled at

the time by
the Khwarezmian Empire.

To defeat it,
Genghis unleashes the fury of

200,000 soldiers.

The Mongol invasion of
Afghanistan was

especially brutal.

JANULIS: He would give quarter
to those who submitted

to his army at the beginning,

but if you resisted no mercy
was shown.

NARRATOR: In 1221,
the Mongols lay siege to

a city to the north of
the site in the image.

In the process of
the siege,

Genghis Khan's favorite
grandson is killed.

Now, this is
going to force instant

and absolutely
brutal retribution.

KOUROUNIS: This was obviously
a very bad decision.

This enraged Genghis Khan.

NARRATOR: To avenge his
grandson's death,

Genghis deploys the first
heavy gunpowder explosives ever

used in combat
to slaughter every man,

woman, and child in the city

and surrounding region.

Khan's wrath knew no bounds.

This city was
put to the knife.

Everybody was killed,
brutalized, and tortured.

Even to this day,
it's known as

the City of Screams
after this massacre.

NARRATOR: What puzzles analysts
is that the site in

the image appears to have been
spared from Genghis's rage.

JANULIS: This fortress continued
to seemingly thrive

for hundreds of years after

the surrounding cities
and fortresses all fell to

the Mongol threat.

NARRATOR: Studies suggest the
key to its survival lies in

its groundbreaking use of
concentric defenses called

curtain walls.

This kind of circle fortress
is something that the Islamic

armies were the first
to perfect.

JANULIS: But each fortified wall
around the city

creates a kill zone
between the next.

It's like taking over
a castle multiple times,

and this was a critical
military innovation,

and that may be why
this city continued

to flourish when everyone
around them did not.

NARRATOR: Some 50 years
after the Mongols' invasion

of Afghanistan,

Christian knights are confronted
by the same defenses

during the Crusades.

Their bloody encounters lead
to a transformation in

the design of forts and
castles across the globe.

JANULIS: Because the Crusaders
saw just how hard it was

to attack one of these
types of fortifications,

they brought it home with them

and started building
it themselves.

NARRATOR:
Over the following centuries,

castles mimicking the Islamic
design spring up across Europe

and beyond.

MORGAN: Ultimately,
you will see them

spreading to North America.

You get forts
in the United States that are

built during the 19th century

that are the expression of an
art that began in Afghanistan.

NARRATOR: Today, the fort
that helped to spark

this extraordinary revolution

in military architecture
worldwide is being swallowed

by the desert.

But for now, its secrets are
still visible from space.

It's fascinating that with
the most modern technology

available to us,
we can look down

and see this thing
that tells us so much

about who we are today
and where we came from.

NARRATOR: Coming up,
hunting shipwrecks from space.

It's easier to identify
massive holes

with hidden treasure.

Every day for five decades,

NASA's Landsat program has
been scanning our planet,

mapping its constantly
evolving surface.

As one of the space agency's
satellites travels over

a patch of sea to
the north of Belgium,

it captures something
that doesn't make sense.

FANARA: What we're seeing here
is vast ocean,

and we're also seeing wakes
from boats.

But then if you look
in the middle,

there are these trails
with no vessel

attached, like phantom wakes.

NARRATOR: The ghostly trails
are almost three miles long.

CAVELL: There's got to be
something sizable under

the water that is creating
this disturbance

so that we can see it
from satellite images.

NARRATOR: Marine scientists
head to the location

and study the seabed
using multi-beam sonar.

MORGAN: These are images
of the sea floor

and they shoot right
through all that silt

and sediment to reveal
what's actually going on,

and it appears that there is

a nest of shipwrecks
in this position.

FANARA: What is happening here
is that the currents moving

around these ships
are causing the sediment

to come to the surface.

NARRATOR: From the Phoenicians,
through to the Romans

and Vikings,
the waters around the wrecks

witnessed trade and warfare
throughout antiquity.

But closer analysis
suggests these wrecks

are casualties
of more recent history.

WALTERS: If they were sunk,
you know, before that,

the boats weren't made out of
metal, so they rotted away.

CAVELL: One of the vessels is
broken completely in half.

I mean, there is some really
violent action that has

taken place on this ship,
and the question is what?

NARRATOR: Analysts
cross-reference the wrecks'

locations with 20th-century
maritime records.

PAVELEC: It turns out that
these two ships are American

Liberty ships,

the Samsip and the Samvern,
that were sunk during

the Second World War.

NARRATOR: Liberty ships were
a class of wartime cargo

vessel and a lifeline
between America and her allies

during the darkest days of
the conflict.

The Liberty ship was
a reflection of the exigencies

of the war effort.

They had to be made quick,
and they didn't have to

last forever.

WALTERS: They were known
as the ugly ducklings,

because they weren't pretty --
it didn't matter.

They got the job done.

NARRATOR: The Liberty ship
program was one of

the most astonishing feats of
engineering in military history.

Between 1941 and 1945,

18 shipyards
across the U.S.

churn out almost 3,000 of
these crafts,

each capable of carrying
10,000 tons of

vital supplies to
a war-torn Europe.

Part of the hull
was poured concrete,

which made it
a really quick turnaround

to actually
construct these ships.

WALTERS: They were
producing these ships

in a matter of hours --
that's extraordinary.

NARRATOR:
Yet these workhorses of war

are also virtually
defenseless, and many ships

and their crews
don't survive the conflict.

These Liberty boats
were quite slow

and incredibly hard
to maneuver.

So at the end of the day,

these ugly ducklings actually
ended up being sitting ducks.

CAVELL: More than 200
would actually be sunk.

But ultimately,
more Liberty ships are

produced than the Germans
can sink.

And so this is
the key to victory.

A discovery of the remains
of two lost

Liberty ships is of great
interest to historians.

But the satellite
image has

a much greater
significance than that.

MUNOZ: These sort of trails
or plumes in the middle of

the ocean are red flags
that could indicate

a shipwreck underneath.

This could really help
governments and authorities

identify other shipwrecks

that could be scattered
across the world's oceans.

NARRATOR: There are
an estimated three million

shipwrecks spread across
the ocean floors.

Until now,
the resting place of many

of these vessels
has been a mystery.

CAVELL:
It's a needle in a haystack

operation to try
and locate shipwrecks.

But the satellites can look
down all day long, any day

they need to, and they can
recognize these plumes.

NARRATOR:
What intrigues many isn't just

the location of these wrecks,

but what they hold.

Over the years,

around $60 billion dollars of
treasure has been claimed by

the ocean depths,

and now, it may be possible
to hunt for it from space.

It's really exciting
to now realize that we have

a clue into where these
shipwrecks might be.

So, if you're
a treasure hunter,

might want to get out
there now.