Original subtitles

Narrator: they're watching you.

More than 4,000 satellites Circle the earth.

Every day, they uncover new, Mysterious phenomena.

Some defy explanation.

Bam! This sticks out Like a sore thumb.

It looks weird.

Narrator: iran's navy Threatens to go nuclear.

This is a real show Of iranian strength.

It's like a full-scale Fireworks display.

Narrator: aerial archaeology Uncovers a sinister structure

Close to the legendary City of petra.

How is it possible That a place as large as this

Has gone undiscovered The entire time?

Narrator: and a monstrous mark Scars the russian wilderness.

This is so strange.

It's like a bite mark Taken out of the ground.

Narrator: baffling phenomenon,

Mysteries from space,

What on earth are they?

**

-- captions by vitac -- Www.Vitac.Com

Captions paid for by Discovery communications

February 2014 -- A satellite photographs

Alarming activity At the gachin shipyard, iran.

This area of the world, The persian gulf in particular,

Is one of the most Photographed areas

On the face of the earth.

Narrator: the shipyard opens Into the strait of hormuz,

A critical artery for most Of the world's oil supplies.

Seventeen million barrels pass Through this channel everyday.

We all know that the iranians Are very fond of referring

To the united states As the great satan.

So we spend a great Deal of effort

In order to know What they're up to.

Narrator: the picture, Taken in 2014,

Raises fears iran could Be up to something.

2013, we have what looks Like an ordinary shipyard.

Fast forward To february of 2014.

And, suddenly, we're seeing Something suspicious.

Narrator: the gachin shipyard Is known for producing tankers

And container ships.

But the new vessel Under construction

Is unlike anything That's been seen here before.

From above, That shape is unmistakable.

Only one thing Looks like that --

An aircraft carrier.

Warren: this was unexpected.

We have not known the iranians

To have an aircraft Carrier capability.

So this is something That we wanted to keep

A very close eye on.

Narrator: the fleet carriers Of the u.S. Navy

Terrify the iranian military

More than any other Type of warship.

They know that, if it comes To war with america,

It will be these ships

Unleashing destruction Upon iran.

If the iranians can deploy One of these super weapons,

They could dominate The region's seas.

This would certainly Indicate a significant shift

In the balance of power.

By march 2014,

The suspicious vessel Is almost finished.

Narrator: new satellite images Reveal a disturbing resemblance

In its shape and design.

This doesn't look just Like any other ship.

It resembles the u.S.S. Nimitz,

The world's premier warship.

These ships carry more Than 5,000 sailors,

Dozens of fighter aircrafts, Helicopters.

They bristle with weaponry.

These capabilities are unmatched Anywhere on earth.

Narrator: The finished ship appears

To be an almost exact copy Of the united states'

Most formidable symbol Of naval supremacy.

It looks, unmistakably, Like a challenge.

Warren: why would the iranians Want to build

A nimitz-class Aircraft carrier?

That's outrageous.

Narrator: For iran, the construction Of a nimitz-style carrier

Would be a mammoth undertaking.

A single vessel costs Almost $5 billion

And requires two fully- Functional nuclear power plants

For its engines.

Is this ship evidence

The iranians have defied International pressure

And secretly developed Nuclear technology?

Only a handful of nations On earth have that capability.

That's really disturbing Because our current intelligence

Says they don't have Anything close to this.

Narrator: if iran can deploy Nuclear-powered vessels,

It means the nation Also has the potential

To develop nuclear weapons.

The idea of a nuclear-capable Iran is frightening.

Narrator: The motive seems clear.

But something Doesn't quite add up.

Advanced nuclear technology Is normally kept top secret.

Moran: Iran is well aware that any time They do something dubious,

It is being captured By satellite imagery.

Orwoll: so if iran were building An aircraft carrier,

Nuclear-powered or otherwise, The obvious question is,

Why do it in full view Of the world?

Moran: another possibility is That iran is doing this

Because they want Everybody to see it.

They want to be provocative.

Could it be political Posturing, taunting?

Narrator: Analysts take a closer look At the satellite images.

Although this is A remarkably good copy

Of a nimitz-class Aircraft carrier,

The length is wrong.

In fact, it's only two-thirds The size of the nimitz itself.

From the top, it looks just like An aircraft carrier,

Kind of except For the size issue.

And in this situation, Size does matter.

Narrator: the presence Of aircraft lined up on the deck

Of the ship offers another clue To iran's intentions.

You don't build An aircraft carrier

And then, put the aircraft on it

While it's still Being constructed.

Narrator: the inconsistencies Puzzle analysts.

Why would the iranians need A pint-sized version

Of the world's Most dangerous warship?

It was very clear to us That they were up to something.

Narrator: just months After its completion,

The ship suddenly vanishes.

The obvious first question is, Where is located now?

Where have they moved it?

Has it gone out to sea?

You need to find it now

To know what they're Doing with this ship.

Narrator: eventually The look-alike nimitz

Does show up as the star

Of a dramatic tv broadcast That grabs world attention.

But this heavyweight killer

Isn't unleashing Any destruction.

It's on the receiving end Of a devastating bombardment

By the iranian navy.

**

Footage appears On iranian television

Showing this vessel

Being attacked By missiles and rockets.

Orwoll: you're seeing Anti-ship missiles.

You're seeing handheld rockets Being launched.

Narrator: it's A military exercise

Intended to prove iran's boast

That they can sink A u.S. Warship

In under a minute.

This is a real show Of iranian strength --

Speedboats, missiles flying at This mock-up of a u.S. Warship.

That's really what the goal was For iran,

Was to show to their people And to the world

That they had the capability

Of sinking Any united states carrier.

Narrator: images From the exercise reveal

The fake aircraft carrier's Shortcomings.

The footage clearly shows Where the explosions

Have blasted away A flimsy outer shell,

Uncovering an ordinary Barge beneath.

Even the jets aren't real.

The whole thing Is a propaganda stunt.

It's basically an elaborate Low-tech hollywood prop.

Narrator: While the iranian navy attempts To intimidate the west,

U.S. Satellites Watch from above.

You have the propaganda machine In iran stating

That they sunk this,

Aircraft carrier During the exercise.

But in reality, they didn't.

They ended up having to tow it Back to the shipyard.

Narrator: photos snatched During the aftermath

Of the exercise confirm

That the barge only Suffered minor damage.

It's difficult for us to know

Exactly what The iranians' intent was.

Frankly, whatever it was They had in mind failed.

Narrator: many western observers Treat the display as a joke.

But to others, The raw aggression

Of the exercise Is a cause for concern.

Some people might Find this silly,

But I don't.

One, for propaganda Within the country to show

That they have This great superpower

Against the united states

And then, Just to show the world,

"Look, we are practicing On striking on you."

Orwoll: this is a dangerous game That they're playing,

This posturing,

Because it doesn't seem To indicate a nation

That's trying to get Along with others,

Not only in the region,

But throughout The rest of the world.

Narrator: satellite images Reveal thousands

Of mysterious mounds

In the shadow Of a sacred mountain.

Whatever's going on here, There's certainly a puzzle.

It almost looks like Bubble wrap.

These mounds are one of the Oldest unsolved

Geologic mysteries.

Narrator: july 2012 --

Satellites passing High above the west coast

Of the united states photograph

Thousands of bizarre Earth mounds.

You see these white Kind of pimpled pock marks

All throughout the landscape.

You've got mounds that are maybe Just a few inches tall

Up to about 160 feet In diameter.

Maybe it's just, like, Random piles of sand.

But why would People pile up sand

In this type of a formation?

Narrator: the mounds are located At the southern tip

Of the cascade mountain range In northern california.

The mysterious features Have puzzled scientists

Since their discovery In the 19th century.

Brand: the last Hundred-some years,

We've had more Than 30 explanations

For how these things formed.

And the fact that We're still debating it

Makes it one of our longest Unsolved mysteries.

Narrator: the mounds In the satellite image

Lie in the shadow of A 14,000-foot-high mountain,

Mount shashta.

There has to be something About this location

That's significant.

Narrator: The mounds' discoverers,

From the u.S. Exploring expedition,

Suspected they might be evidence

Of a gigantic native American graveyard.

I've come across these In the field and thought,

"Wow, these must be Burial mounds."

Narrator: the local wintu tribes Are known to bury their dead

In earth-mounds Near the sacred mountain.

Watkins: mount shashta overlooks Hundreds and hundreds

Of these mounds.

If these are burial mounds, What must have happened?

Was there an outbreak Of disease?

Was there a huge battle?

People had to be Mass buried in a hurry.

Krueger: if this is some type Of native american cemetery,

Are we looking at

The aftermath of some type Of great conflict

That happened in the past?

Narrator: archaeologists Have searched this area

For signs of a battle Or catastrophic epidemic.

Recent tests have shown That there are no human remains

In any of these mounds.

And we haven't found Any artifacts either.

**

Narrator: there's nothing sacred

About this particular Stretch of prairie.

But nearby mount shashta Has inspired legends,

Which could shed light On the nature

Of the mysterious mounds.

One in particular describes A mystical underground city

Located within the mountain.

Not everything I hear About the mountain I believe in.

But that doesn't mean It's not true.

I just haven't experienced it.

Narrator: according To the legend,

When a continent called lemuria Was destroyed,

The inhabitants needed to choose

Where to build Their new settlements.

Ashalyn: one of the places Some of the people ended up

Was underneath mount shashta

In the volcanic lava Caverns there.

And it's called The crystal city of telos.

Narrator: the mountain does have A network of tunnels.

And digging them out could have

Brought heaps of earth To the surface.

But searches of mount shashta Have uncovered

No scientific evidence For an underground city.

People haven't Caused these mounds,

But something has.

The only question is, what?

It's a great example Of having to go exploring,

Having to analyze on the ground

To understand a feature.

Okay, bring it up here.

Narrator: The mystery of the mounds Has attracted scientists

From the university Of california at davis.

There's this huge mystery, What formed these mounds?

Several different theories Have been proposed.

And our goal here today is To see if there's any evidence

That would allow us to determine How these mounds formed.

Narrator: one theory is That the mounds

Are sediment deposited From mount shashta's glaciers.

Dahlgren: during the melting Of the glaciers,

A lot of material Would have been mobilized.

And among that material

That comes off In the glacial waters

Is a lot of fine particles, The silts, the sands.

Brand: glaciers can create a lot Of very strange land forms

Just from a sub-glacial river

That transport a lot of sand And gravel leaving a mound.

Narrator: as melt waters flow Down slopes away from glaciers,

They tend to deposit sediment Along the direction of flow

In fairly straight lines

Pointing away From the mountain.

If we saw linear pathways Through this landscape here,

Then we would start to think About glacial out-wash

As being a mechanism.

Narrator: To test the glacier theory,

The team uses a drone To map the precise layout

Of the mounds.

Dahlgren: from looking at The information from the drone,

We don't see That linear striation

That would be indicative Of water-transported material.

That's a very important Piece of the puzzle.

To really understand What formed them,

We really need To dig into the soils

To see what's there.

Narrator: the soil sample Contains a tell-tale clue

To what really Formed the mounds.

The color is uniformly dark.

And that darkness Is coming from organic matter.

So how did that organic matter Get from the surface

All the way down to 2 feet?

Well, this is consistent With mixing by animal.

And on this landscape,

The number one soil animal

That mixes it Are pocket gophers.

**

Some have suggested that gophers Are moving material around.

That doesn't seem Too plausible to me.

Given the size and the sheer Number of these mounds,

As a geologist, it's hard for us To think about animals

Creating something like this.

Narrator: but the ground radar Sweeps suggest the mounds

Have been made by gophers.

Mccarten: we can search For air space

So we can map out The network of tunnels.

Narrator: the tunnels run Through every mound.

And the evidence Is even at the surface.

Just down for the major part Of the mound here,

I found a series Of two gopher holes.

Narrator: the gophers push Soil and pebbles upwards

As they create their burrows,

Slowly adding layer Upon layer.

Thousands of these Little critters

Are frantically working away.

But why would gophers want To build massive dirt mounds?

These areas get saturated.

And, if you have a gopher hole That's in a soil

That's saturated, That gopher's gonna get all wet.

So, by building These mounds,

They get up and above This water table,

Which keeps them dry.

Narrator: according To computer models,

It would take gophers 700 years

To construct these vast mounds.

If you consider A family of gophers,

Generations and generations Of gophers

That build these over time,

Maybe that could work.

That's pretty cool,

That a little gopher Can have a signature

That's seen from Hundreds of miles up.

**

Narrator: an eye in the sky Discovers a stone platform

That could reveal a violent,

Untold chapter In the history of petra.

It's very possible That hundreds or possibly

Thousands of people Would come to this monument.

Narrator: like the legendary Tomb of tutankhamen.

It's remained hidden Beneath the desert sand

For thousands of years.

Kourounis: this discovery Could change everything.

It could actually rewrite The history books

And everything we know about Middle-eastern archaeology.

**

Narrator: analysts studying Pleiades' satellite images

Of jordan spot a strange shape In the desert sand,

A football-field-sized rectangle

That has somehow eluded Archaeologists for decades.

Tuttle: the evolutions In technology,

Especially With satellite imagery,

Really is a game changer Now for archaeology.

This image is very subtle. But dead center...

There's a fairly pronounced

Rectangle that stands out Against the background.

Narrator: for investigators, The location is intriguing.

It stands less than a mile

From petra's fabled Ancient monuments.

Gijseghem: petra, The city is, rightfully,

One of the archaeological Wonders of the world.

Kourounis: petra is Very well known.

It was even used in "Indiana Jones and the last crusade"

As the city where they find The holy grail.

**

Narrator: few of the tourists Who visit here realize

That this is a city Obsessed with death.

The site is littered With more than 1,000 tombs

Engraved with curses.

And its most famous monument, The treasury,

Was built to honor the dead.

Tuttle: kings may have been Divinized upon their death.

So it has also been hypothesized

That this served A bit as a temple

In the worship Of that deceased king.

Narrator: the satellite image Could be evidence

Of undiscovered secrets

Still hidden around The ghostly city.

Thanks to the images,

We will be able to get actual Measurements of this monument,

Which is very, very large.

It's about 180 feet per side.

Seems to be, potentially,

A religious platform Of some sort,

Perhaps an arena of some sort.

Narrator: a clue to the Structure's function could come

From another religious platform Discovered at petra.

It's known as The high place of sacrifice,

An area dedicated To ritual killing.

It's not unusual In ancient societies,

To find these very carefully Prepared communal spaces

That are used for displays

Of power and rituals And ceremonies.

**

Narrator: the founders of petra, The nabataeans,

Are rumored to have Slain children

As offerings to their gods.

The new discovery Is almost four times bigger

Than the high place Of sacrifice.

Could it point to bloodletting On a much bigger scale

Than previously believed?

Kourounis: this discovery Could change everything.

It could actually rewrite The history books

And everything we know about Middle-eastern archaeology.

Narrator: in 2016, archaeologist

Christopher tuttle Visits the site.

His study of the stone Masonry concludes

That it's part of A genuinely ancient structure.

Tuttle: I remember the first time I walked to the site.

And knowing it was, In fact, a monument

Was a great relevatory moment.

Narrator: the discovery Of the remains

Of a giant staircase leading up To the structure raises

A new and intriguing possibility

For what it could be --

A vast arena For massive public events.

People, in order To get to the site,

Would've had to work their way

Through a series of Interconnected small valleys

And then climb up This monumental staircase.

If it's an arena, One possibility is

That there would of been A kind of public gathering

For contests, Like gladiator displays perhaps.

Narrator: an arena this size Could have hosted

The gladiatorial super bowls Of its era

With huge crowds coming here

To witness ferocious Battles to the death.

Artifacts found at the site Indicate it was built

Around the time that rome saw Its first gladiators.

Tuttle: the pottery that was Found on the surface tells us

That it could have been built As early as the beginning

Of the founding Of the city of petra,

Which was about the middle Of the second century, b.C.

Narrator: when analysts study A drone image of the site,

They discover another clue -- Evidence of a small building.

Tuttle: based on what Little bit of architecture

We can see that's there today,

We really think that This was most likely

Some sort of sacred shrine.

Narrator: the purpose of this Sacred spot is unknown.

If the remains of sacrificial Victims lie here,

They are yet to be discovered.

Despite The structure's proximity

To one of the world's most Famous archaeological sites,

It still holds secrets.

Archaeologists have been pouring

Over the petra site for decades.

How is it possible that,

In a place where there's been So much excavation

And so much discovery, That a place as large as this

Has gone undiscovered The entire time?

Narrator: was it deliberately Destroyed by its creators

To conceal evidence Of their barbaric bloodletting?

Or demolished By rampaging conquerors

In some long-forgotten war?

For now, what lies beneath These sands remains an enigma.

The internet lights up When an eye in the sky

Photographs a car appearing To mock the law of gravity.

There's some things on earth When we see them from space

That just make Absolutely no sense.

This is an image Which totally defies logic.

It almost feels Like the movie "Inception,"

Where the world Is just topsy-turvy,

Flipping over itself.

Narrator: an arrow data Eye in the sky passes over

The hague, netherlands.

It photographs Something that appears

To defy the laws of nature.

When I see a car parked On the side of a building,

I have to start wondering If I'm in "The matrix."

Porges: this is strange.

There's no way this Could be really a car

Stuck to the side of a building.

Narrator: if it's not An actual car,

The simplest explanation is That it's an optical illusion.

We've seen these Optical illusions before.

A few years ago, someone spotted What looked like a flying car.

Narrator: the famous flying car

Was spotted In perth, australia.

The image went viral And prompted a frenzy

Of speculation About what it really was.

At first glance, This looks really weird, right?

This white car is floating With its shadow underneath it.

There is no question. This is very strange.

Narrator: the explanation For the flying car

Is that it's a trick of the mind

Where the brain misinterprets Light and shade.

It turns out that This image is nothing

But a white car Parked next to a black car.

Once you realize that,

It's completely obvious What you're looking at.

Narrator: detailed examination Of the mysterious car

On the side Of a building reveals

It can't be the result Of a similar optical illusion.

Not only is the car stuck To the side of the building,

But so are The road markings.

Narrator: Some internet speculation Around the image

Suggests it could be A computer glitch.

Data processing errors Can sometimes transform

An ordinary satellite photograph Into something surreal.

There's this thing Called the escher effect.

It's named after The artist m.C. Escher

Who'd draw these Impossible structures.

It's when tall buildings In satellite images,

They appear to defy The very laws of physics.

Narrator: the effect is caused By the way computers

Put satellite images together.

The effect itself is A real mind-bender.

The pictures are super trippy.

But the explanation itself Is actually really simple.

As a satellite makes consecutive Orbits around the earth,

It doesn't pass The same place twice.

One satellite pass that captured This set of buildings

And then another satellite pass

Which captured this Set of buildings.

To a stitching program,

Which puts all those images Together, it doesn't care.

It just needs to know That this coordinate

Is next to this Geographical coordinate.

And it puts 'em Next to each other.

Narrator: While the escher effect Is fairly common,

It can't be responsible For the mystery image.

Problem is the escher effect Only really happens

To tall buildings, Things like skyscrapers.

Narrator: Investigation at the site

Of the gravity-defying car Reveals the surprising answer.

The truth of the situation Is a lot more down to earth.

What we're actually looking At is an art installation.

The piece is called "Extreme parking".

It's by an artist Named theo van laar.

And he's extended the parking Lot up the side of the building.

That's an actual mini Cooper up there.

Narrator: van laar created The work to demonstrate

How congested our towns And cities have become.

He had no idea that his piece Could be seen from space.

I never looked at google earth.

But somebody sent me An e-mail note,

"You have to look." And then I looked.

And there it was.

And I thought it was Very, very nice.

Narrator: remarkably, Van laar's car is still

Parked on a wall over 30 years After he raised it up

Using a specially adapted crane

And 16 high-strength bolts.

This image is exactly What it appears to be.

It's a car that's parked On the side of a building.

Narrator: Strange markings spotted deep In russia's caucasus mountains

Pose disturbing questions.

Clearly, Something's created it.

What? Force of nature or man?

You have to ask why Would anyone build

Such a structure up In the mountains?

Narrator: Russia, october 2004 --

During an inspection Of aerial photographs

From the soviet union,

Archaeologists discover a series Of weird shapes on the ground.

Podges: this is so strange.

It's like a bite mark Taken out of the ground.

This is one of these things Where you really don't know

What's going on.

If I was looking at it, And I was in the military,

I'd want to investigate.

I wouldn't be happy To leave that alone.

Narrator: the photograph Dates from the 1970s.

But all other information About it has been lost.

The only thing Investigators know

Is that it was taken somewhere

Over the caucasus mountains In southern russia.

Petford: the caucasus Mountain range

Is one of the less known Mountain ranges on the planet.

But it's actually a very, Very big range.

Narrator: to try to uncover The exact location of the site,

Image analysts compare The old aerial photo

With modern topographical maps.

The shape appears to be in The foothills of mount elbrus --

Europe's tallest mountain.

This newfound information raises The possibility that the scar

Could be connected To another local mystery.

Back in 1948, a soviet plane

Went missing Between azerbaijan and georgia.

And to this day, We don't know what happened.

Narrator: The location of the image Is tantalizingly close

To the flight path Of the missing soviet plane.

It leads some to suspect This could be the crash site.

Podges: the missing plane's Planned flight course

Was just 165 miles south Of this site.

That's barely any distance

If the plane went off course

Even a little bit.

Narrator: the unpredictable Weather around mount elbrus

Could easily have Brought down an old plane.

But the image Doesn't back up the theory.

Podges: there's no Visible debris.

I don't see any wings, No tires, no engines.

If this was a plane crash, It was a very neat one.

Narrator: analysts consider What else could have made

Such a bizarre imprint On the mountain.

It looks like something that Would've been created by humans.

But we have to ask, also, "Why would anyone build

Such a structure Up in the mountains?"

Narrator: one possible answer Has sinister indications.

Narrator: In the old soviet union,

Isolated parts of the country Often concealed dark secrets.

The soviet union used Remote locations

As a way of making people... Disappear.

Narrator: under joseph stalin's Tyrannical rule,

18 million men and women were Sent to brutal labor camps

Called gulags

At the most hostile frontiers Of the red empire.

While many gulag camps Are a matter of public record,

Others remain Top-secret and classified.

And we don't know Where they are.

Narrator: the circular, Cell-like shapes

Around the edge of the structure Support the idea

That this could be The remains of a gulag.

There was, in many ways, No rhyme or reason

To why you ended up in a gulag.

People would arrive having No idea what their crime was.

If you went to the gulag, It was literally hell on earth.

You were nowhere near Your friends and family.

And the labor Was utterly exhausting.

People were worked to death.

**

Narrator: the image doesn't Show any evidence

Of watch towers or fences.

But gulags often Didn't need them.

Robertshaw: the gulags were Very, very simple.

They were camps where, Basically,

You didn't need to have Barbed wire, many guards.

Why? 'cause, if you leave,

If you get out, You're gonna die.

There's just nowhere to go.

Narrator: the isolated location

Would explain the simplicity Of the structure.

But closer inspection Of the image reveals

A detail which casts doubt On the gulag theory.

Altaweel: this feature seems To be made out of stone.

So I don't think this Is evidence of a gulag.

Gulags generally don't have Wall-remains made of stone.

Narrator: for years After its discovery,

The structure remained Unexcavated

Until a team of archaeologists,

Led by sabine reinhold, Stumbled across the site.

We were traveling in the area,

Doing survey there.

And our driver said, "Okay. Look.

At the end of the bush, There is something."

And we weren't sure at the time.

We said, "Oh, no, no, no."

But we decided to go there.

When we arrived at the site,

We understood that We have discovered a real,

New archaeological phenomenon,

Absolutely unknown features

And unknown things

Nobody had seen ever In this area.

It was clear that it Is a settlement.

It was clear because It was possible to decide

That these are houses.

We found a lot of ceramics

And animals bones On the surface.

Narrator: no one knows Who these people were

Or how they came to be here.

But the construction methods

Used suggest the site Is truly ancient.

There's no written records

Of any colony In these mountains.

So you got to ask, Just how old is this place?

It's not clear. But we know, in the bronze age,

Which was about 4,000 years ago,

People were building Features like this.

Narrator: radio carbon dating Puts the age at 3,600 years old,

The right ballpark For the bronze age.

It also reveals Something extraordinary.

The people who lived here

Survived on this Harsh mountainside

For over 1,000 years...

And then vanished.

In these high mountain plateaus, It's rather harsh and windy.

And it's not the best place To live constantly.

But then they stayed there For about 1,000 years.

And then, suddenly, they moved.

But why they moved, We don't know.

Narrator: perhaps the conditions Became too harsh for them.

Or perhaps they were taken Against their will.

All we do know is that, Over 3,000 years ago,

Some enigmatic people chose

This desolate site To make their home.

It's so little to go on.

We may never know who they were

And why they built This impressive complex.

Narrator: a social media storm Draws high-tech surveillance

To one of the world's Biggest manhunts.

Green: This is one of the world's Deadliest terrorist groups.

Without warning, 276 girls disappear.

How do almost 300 people Go missing without

Anyone knowing Where they've gone?

Narrator: across the globe, State-of-the-art aerial imagery

Is being used to hunt

For the world's Most wanted terrorists.

In april 2014, A shocking attack

On a school directs The gaze of satellites

To a remote corner Of sub-saharan africa.

Fighters from The boca haram guerrilla group

Stormed into a school at chibok In northeastern nigeria

And kidnapped 276 schoolgirls.

Narrator: the mass kidnapping

Sparks outrage Across global media.

It was an attack That took the world

Completely by surprise.

Suddenly, there was An outpouring

Of concern on social media.

We saw the hashtag, #bringbackourgirls.

Everybody can probably Remember that picture

Of michelle obama Holding up that sign.

Everybody suddenly wanted To get these girls back.

Bale: the school that the girls Were kidnapped from was

Actually a government school

Where they were teaching People science and math.

[ shouting ]

[ gunfire ]

Pavelec: The incredible thing is, They just seemed to disappear.

How can that many people be Hidden anywhere on this planet?

Narrator: authorities Use satellites to search

For the suspected perpetrators,

The extreme islamic terror Group, boco haram,

Who've spent over A decade seizing control

Over large swaths Of northeast nigeria.

Goal of the group, boca haram,

Is to establish An islamic state.

Of course, the name of the group Literally means,

"Western influence or western Education is forbidden."

They're driven towards power.

They're incredibly violent,

And they conduct raids And murder and rape.

Narrator: as soon as the search For the kidnapped girls begins,

Military and civilian satellites

Urgently direct their cameras

Towards the terrorists' Last-known hideout

Near the border with cameroon.

Blasina: It was an incredible display Of international cooperation.

You know, the u.S., the french,

All of these different countries Stepped in to find these girls.

Narrator: the satellites are Attempting to pinpoint

The schoolgirls in an area

Nearly the size Of south carolina.

Green: fact of the matter is,

This is ideal country For guerrilla operations.

We're talking about a very Remote area, forest, hills,

And the rebels always seem To be one step ahead.

Narrator: Despite knowing the rough Whereabouts of the girls,

A months-long search fails To pinpoint a precise location.

To make matters worse,

Boca haram continued To terrorize the region,

Kidnapping more children And raiding villages.

Koettl: boca haram Does not have, like,

One specific headquarters That they operate out from.

They move around very quickly. They're very mobile.

That's their advantage.

They can play A cat-and-mouse game

With the security forces.

They can leave A very light footprint.

It's very difficult For the authorities to keep up.

Pavelec: finding These kidnapped schoolgirls

Is an incredibly difficult task.

But boca haram is A growing organization.

And they leave traces Everywhere that they go.

Narrator: nine months After the girls' abduction,

Satellites detect boca haram's Current whereabouts.

Two images of a village,

Taken just one week apart,

Expose the scale Of their latest atrocity.

2015 -- boca haram committed One of the biggest attacks

That they have ever done.

Narrator: terrorism expert Melissa hanham

Analyzes the images for clues

That might reveal a connection With the kidnappers.

We're trying to see Where attacks have happened.

This is a healthy village

That has just what you would Normally expect --

Cars, tidy roadways,

Lots of healthy trees.

These people Are probably farmers.

There are no Military targets here.

There's no access To independent observers

Of independent reporters.

So we deployed satellite images To see what's going on.

And it was a really Shocking picture, what we saw.

2,000 people are feared To have been killed

In the barbaric massacre.

Hanham: walls we were Looking at before

Are now completely gone.

You see blast marks.

All of this are homes that have Just been reduced to rubble.

Narrator: satellites focus Their attention

Around this And other devastating villages,

Hoping for signs Of the girls' whereabouts.

While they identified Many villages

That had suffered really, Just catastrophic damage,

They had not, unfortunately,

Been able to find The girls themselves.

Green: with all this Satellite technology,

One would think that it Would be possible

To at least narrow down the area

Where these girls Have disappeared to.

But it seems like they've Vanished into thin air.

Narrator: the manhunt Finally gets a lead

When several of the girls Manage to escape.

Blasina: some of the girls Have been able to escape.

But there are still More than 200 girls missing.

So we're not in a position To stop looking yet.

Narrator: the free girls provide Authorities with information

About where the survivors Are still being held.

Some of them are already Explaining where they came from.

Narrator: satellites are joined By military drones

To pinpoint The precise location.

The satellite is In orbit over the earth.

On the other hand, a drone can Maintain surveillance on a spot.

Then, you can get a better image

Of what's going on On the planet.

Narrator: drones catch glimpses Of boca haram

And even attack teams Of terrorist gunmen.

But there is still no sign Of the missing girls.

Authorities are forced To try radical new techniques.

Amnesty international Image specialist

Christoph koettl analyzes

The terrorists' Smart phone footage

And cross-references it With satellite data.

A lot of people use Camera-enabled cell phones.

And they document everything That's going on around them.

That allows me To use the footage

And match it up With satellite imagery

And confirm The exact location,

Sometimes, you know, Only maybe the town.

But, in a lot of cases, we can

Really zoom in On a specific house.

And we know the exact Street corner

Where something has happened.

Narrator: but boca haram seemed

To be growing wise To these techniques.

When the militants release

A video showing the girls They still have captive,

They disguise the background To hide their location.

The search for The surviving girls is ongoing.

Pavelec: although some Of the schoolgirls

Have escaped from boca Haram's clutches,

A lot of them are still In captivity.

We are not gonna stop Until we've found them

And rescued them.