Original subtitles

[tense music]

- Mysteries can be buried anywhere.

Under the earth.

[volcano booms] [engine whirring]

Beneath the sea.

Or even right under our own feet.

And when we stumble upon them,

sometimes what we find can change history.

Tonight, military secrets from a highly classified message

hidden in a chimney.

- The message is revealing German positions in Normandy

prior to the D-Day assault.

- To one of the Nazi's most potent weapons

lurking in the deep.

- It was an incredible German invention of World War II

which allowed them to send encrypted messages.

- To a Cold War hotspot buried under the ice.

- The US assumes its secrets will be buried deeply

underneath the ice,

but these researchers upset all that.

- Join us now, because nothing stays hidden forever.

[mysterious music]

Let's say you're part of a team working out in the forest.

You're cutting down trees on what feels like a normal day.

Then, you accidentally find something incredible.

- One of the team members, Kit Rodger,

is wading through dense foliage.

The team's getting ready for a large scale operation.

[saw whirring] [tree cracking]

- Just as they're about to begin,

Kit Rodger spots something on the ground

that definitely is not a tree.

- He looks down, he sees an iron door.

- Curious, he pries the door open

and sees a small shaft leading down.

He decides to investigate

and what he finds is a buried bunker.

- The chamber's about 23 feet long, 10 feet wide.

There's some broken timber bed frames,

but really nothing else survives inside the structure.

At the far end, though, there's an escape hatch.

- He thinks he's found something special

that's long been rumored to have been hidden in this area.

One of the famous Churchill bunkers.

- [Narrator] The Churchill bunkers were built

as part of a secret operation

during some of the darkest days of World War II.

[alarm blaring]

- Beginning in September 1940,

England had been subjected

to a protracted strategic bombing campaign.

[explosions booming]

- Basically, the Germans, for eight months,

are raining fire down on England,

intense bombings of places like Coventry and London.

This attack is known as the Blitz.

- Fearing that the Germans might conduct

an invasion of some kind,

British Prime Minister Winston Churchill

creates a clandestine organization

that he calls the Auxiliary Units.

- [Narrator] Unofficially, they're known

as Churchill's Secret Army.

- This isn't some sort of an elite unit.

These men are farmers and miners.

But they bring one critical advantage to the scenario,

and that is an intimate familiarity with the land.

- The main purpose of these units

is to act as a resistance force

in case the Germans do invade.

- [Narrator] This is an army designed to fight to the death

as a last resort.

Essentially, it's a suicide mission.

- To give this force a chance against an invading army,

they need the element of surprise.

- So, all across Britain, an estimated

500 of these Churchill bunkers were constructed

in order to house this army.

- Their locations are secret

and their entrances are disguised

so they can't be seen from the air.

- Fortunately, Churchill's last-ditch army

is never called into service, and that's because of the fact

that the Nazis do not invade the United Kingdom.

- [Narrator] A few years later,

when World War II comes to a close,

Churchill's Secret Army is disbanded

and the bunkers are abandoned.

- The locations of these bunkers have never been confirmed,

and to date, just about 200 of them have been found.

- Investigators are sent out

to examine the underground position

and compare it against other known Churchill bunkers.

And what they discover is it is a perfect match.

This is indeed a Churchill bunker.

- The location of this newly discovered bunker

still remains a secret to this day.

- But who knows? If you're out and about

wandering around the English countryside,

you might stumble across one of the ones

that has yet to be discovered.

- Not every military secret is buried underground.

Sometimes, they hide in plain sight.

- It's 1977 and Peter Johnson is walking along Martin Bay

at the tip of the Canadian province

of Newfoundland and Labrador.

- The terrain here, it's cold, it's vast.

The site is so remote

that fewer than 600 people visit it each year.

Johnson is there to conduct an investigation

about the native people that once lived there.

- The nearest town is 100 miles away

and it's just a small outpost of about 1,100 people.

Out here, you're more likely to meet a polar bear

than another human.

- [Narrator] As he crosses a rocky edge of earth,

he sees something strange in the distance.

- And what he sees looks like a series of drums

with a flagpole in the middle.

There's nothing else like that

out in the middle of this barren wasteland.

- It's clearly been abandoned for some time,

which only adds to the mystery.

He dismisses it as some sort of old Canadian weather station

and just jots it down in his notes as "Martin Bay 7"

and then just moves on.

- [Narrator] But that's not the end of the story.

Four years later, a German researcher,

Franz Selinger, makes a surprising discovery

about this mysterious weather station.

- As Selinger is going through the research files,

he finds one that is labeled "Kurt."

When he opens the file,

it consists of a series of photographs that depict a U-boat

and then also some equipment installed

in this snow-covered Arctic environment.

- He notices that the U-boat is not configured

like other U-boats,

in that it's missing its quadruple anti-aircraft gun,

which he finds interesting.

So he decides to look into the German U-boat logs

and eventually comes across the log for U-537.

- [Narrator] Selinger discovers something extraordinary.

A secret mission

to set up a weather station in Newfoundland.

But why would the Nazis go through the trouble

of setting up a station here,

thousands of miles from the front lines?

- Having the ability to forecast weather with high accuracy

can provide a strategic advantage in combat.

- Because the weather in North America basically determines

what the weather's gonna be like in Europe a few days later,

if you know what the weather's gonna be like

and your enemy doesn't, you have an advantage.

So this weather station can be the difference for the Nazis

between victory and defeat.

- [Narrator] Before Selinger's find,

historians believed that the Nazis

had never set foot in Canada.

- It was well known, of course,

that German U-boats operated on the Atlantic coast

and the coast of the Gulf of Mexico,

but it's believed that's as close as they ever got.

The captain of U-537 selects Martin Bay specifically

because it's a sparsely populated part of Labrador,

and they select the time period

because when they sail into this remote bay

and install the weather station,

within two weeks, the entire bay will freeze up

and then nobody can get to it.

- The setup team loads their equipment

onto these small rubber dinghies,

brings them to shore,

sets up the structure, tests it.

They quickly get back on the U-boat,

submerge, and head out to sea.

- [Narrator] Although the Nazis complete the mission undetected,

not everything goes according to plan.

- The ironic thing is that the Germans could send a U-boat

thousands of miles from home base

to set up a state-of-the-art weather facility in Canada

only to have it work for about three weeks

due to the fact that the elements in Canada

degraded the station so badly

that it couldn't transmit useful data anymore.

- [Narrator] In 1981, Canadian officials send a historian

to relocate and preserve the site.

- And he finds that the weather station is still there.

It looks weathered, part of it is damaged,

it looks like maybe animals have gotten to it,

but it is still there.

- The weather station today

can be found at the Canadian War Museum in Ottawa.

- And that weather station provides proof that Nazi Germany

conducted an armed and uniformed landing in North America

during the Second World War.

It also begs the question,

what else might be out there from World War II,

in some remote part of the globe,

just waiting to be discovered?

- X-rays are supposed to reveal what's going on

inside our bodies.

But in the 1940s,

they accidentally exposed something classified.

- The Kodak Company,

headquartered in Rochester, New York,

is probably best known for making film.

You know, back when those were used in cameras

before everything went digital.

- But Kodak doesn't just make film for cameras,

they also make everything necessary for X-ray imaging

in a medical capacity.

- Around July of 1945, however,

they're starting to get a lot of complaints

from some of their customers

regarding their X-ray film.

- It turns out the complaints are all remarkably similar.

The images come out foggy with black dots all over the film.

- These complaints come as a surprise

to the scientists at Kodak

because they take incredibly good care

in preparing the film before it's shipped out.

This is because they know it's extremely sensitive to light.

- [Narrator] Everything involved

with prepping and shipping the film is handled carefully,

but with so many unhappy customers,

Kodak assigns a scientist named Julian Webb to investigate.

- Webb's investigation reveals

that the contamination was in the packaging,

not in the film,

and that the packaging came from a plant in Indiana.

But more surprising and disturbing

is that the contamination itself is radioactive.

- It's a shocking discovery.

But what he also finds out

is that there are problems from another plant

that's making this film,

but this one is all the way over in Iowa.

- So, over the next few weeks,

Webb and his team examine both plants and realize

there's nothing that could account for these issues.

- [Narrator] Then, on August 6th,

Webb gets a clue about what could be causing the problem.

[explosion booms]

When the US drops a nuclear bomb on Hiroshima.

- In the weeks following

the dropping of the atomic bombs on Japan,

it eventually emerges that the US,

on the 16th of July, 1945,

had carried out, in great secrecy,

the first atom bomb test in New Mexico.

- It's the culmination of what's called

the Manhattan Project,

a years-long top secret attempt to build an atomic bomb.

At the time, the government tried to cover it up

by saying it was just a detonation

of conventional explosives.

Nobody really questions it.

I mean, there's a war going on, this is World War II.

- Julian Webb begins to connect the dots.

He realizes while the government could control the spin,

they couldn't control the spread of the radioactive isotopes

from the explosion.

And wind scattered these radioactive particles

far and wide, eventually landing in the river water

that supplied both the Indiana and Iowa factories.

- Webb has discovered something

that perhaps the government doesn't even know

or doesn't want to know,

that these radioactive particles can spread incredibly far.

- As a result, Kodak puts Geiger counters at its facilities

to monitor radiation levels

in the production of their films.

[alarm blaring]

- In 1951, the counters go wild

because of a test in the Nevada desert.

Claiming to be losing money from product loss,

they threaten to sue the US government.

- [Narrator] The government doesn't want

this information made public,

so they make a secret deal with Kodak.

- They agree to give them a heads up about any future tests

so they can protect their product,

and the public is none the wiser.

- If Rochester, New York seems like a surprising place

to discover nuclear secrets,

what about Greenland?

- In 1995, a group of Danish researchers

are at the US National Archives in Washington.

What they're looking for are records of flights

made over Greenland during the Cold War.

- While looking through the files,

they find one curiously titled,

"Europe: January to May, 1962."

So they open it up.

- This folder has nothing to do with flight times

or air cargo.

It, in fact, leads not to the air, but below the ice.

- [Narrator] They discover files

describing something called Project Iceworm,

and it's a doozy.

A daring, covert operation

that seems straight out of a Cold War spy novel.

- In 1959, Northern Greenland is buzzing

with a construction project

unlike anything ever attempted before.

- Just 800 miles from the North Pole,

the US Army Corps of Engineers

is building what is known as the city under the ice.

- [Narrator] It's called Camp Century

and it's being used to conduct scientific research.

- Camp Century has just about everything

that you could expect to find in an American small town.

The main tunnel is 1,000 feet long

and it's called Main Street.

It has a chapel, a hospital, and even a movie theater.

- It's basically all powered

by the world's first mobile atomic generator,

the PM-2A, A for Arctic.

The camp captures the nation's imagination

and the attention of major newspapers, magazines,

and of course television,

including the most trusted man in America, Walter Cronkite.

- And he brings this film crew and they highlight

all of the scientific experiments that are going on

and all the wondrous research that they're doing

under the ice pack.

- [Narrator] What Cronkite doesn't know

is that Camp Century is a cover for a Cold War project

with much higher stakes.

Creating a secret US nuclear base close to Russia.

- And part of this plan

is to build 2,500 miles worth of tunnels

so we can base new intercontinental,

ballistic missiles there in Greenland.

- And the US military is planning to build a railway

connecting these hundreds of miles of tunnels

so that 600 nuclear-tipped missiles

can be moved between 2,100 launch sites

under the Arctic ice.

- On paper, this plan looks like a winner.

By keeping the missiles both under the ice and mobile,

you keep the enemy guessing.

The idea is to be able to move

the missiles around strategically

to stay one step ahead.

So it's kind of like a game of nuclear whack-a-mole.

- Each one of these missiles

that the US plans to base in the Arctic

will carry a warhead 150 times more potent

than the atom bombs dropped on Hiroshima and Nagasaki.

- Putting the missiles in this location

allows you to target up to 800 miles into the Soviet Union,

thereby hitting most of their industrial capacity

and the military targets that are around them.

- The project is so top secret

that even Denmark, who oversees Greenland,

they don't know about it.

- [Narrator] There's just one surprising problem.

- Greenland's ice sheet is in fact constantly moving.

It rolls and heaves just like the sea,

but at a very slow pace.

The shifting ice wreaks havoc on Camp Century.

Tunnels collapse, and there's a five-foot sag

in the ceiling of the nuclear reactor room.

- Eventually, the US military faces the inevitable.

You can't beat Mother Nature.

- So, in 1966, the US gives up,

it packs up, and it abandons Camp Century.

- The US assumes its secrets will be buried deeply

underneath the ice.

But these Danish researchers upset all that,

leading to another wild Cold War discovery.

- Imagine you're a diver cleaning up lost fishing nets

when your sonar goes off.

What you discover next isn't what you were expecting.

- Off the coast of Germany, in the Bay of Gelting,

the World Wildlife Fund drops a diver into the water

to retrieve a missing net.

As he gets closer,

he notices that the net is hooked

onto this odd-looking dark rock

with these white specs on it.

- Upon closer inspection,

he realizes that the white specs are actually characters

on what appears to be an old typewriter.

Since an old typewriter is really out of place

on the seafloor, he decides to pull it up.

- Once they get the object out of the water

and they take a close look at it,

they realize this actually isn't a typewriter at all.

- [Narrator] This strange discovery

is a Nazi M3 Enigma cipher machine.

- The Enigma machine was an incredible German invention

of World War II

which allowed them to send encrypted messages

between their various political, military,

and naval headquarters.

- [Narrator] The Germans think their system is unbreakable.

- There were at least 159 trillion possible solutions

to the codes the Enigma machines created.

- What's more, the code key changes every 24 hours.

The Allies tried to crack the Enigma system

time and time again, only to fail.

- [Narrator] But Britain's leaders know

breaking the code is critical,

so they recruit a top secret team

to work at Bletchley Park,

Britain's code-breaking center.

- In 1941, they break through

and figure out how to crack Enigma.

- This is a complete game changer for the Allies

because it allows them to read German communications

in real time.

- It's believed that cracking German naval Enigma alone

ended the Second World War one year earlier

than it would've ended otherwise.

- [Narrator] How did this crucial piece

of the Nazi war machine

wind up at the bottom of a bay?

- By the spring of 1945, the Allies had the upper hand

against the faltering German forces.

The end of the war in Europe is in sight.

- Shortly before the German surrender in May 1945,

the German high command orders

Operation Regenbogen, Operation Rainbow,

by which they ordered both the U-boats and surface vessels

to scuttle themselves, sink themselves deliberately.

[explosion booms]

So they could not be seized by the Allies after the war.

- In Gelting Bay alone,

around 50 U-boats are sent to the bottom,

many of them carrying Enigma machines.

- [Narrator] While over 40,000 Enigmas

were made during the war,

less than 300 remain,

so the diver's find is potentially worth serious money.

- Enigma machines have sold at auction

from between 50,000 to $500,000.

- [Narrator] But instead of selling the machine,

the divers donate it.

- The divers turn over the Enigma to researchers.

Today, if you go to the Museum of Archeology in Schleswig,

you can see the machine on display.

And it's kind of cool because it also serves as a reminder

of the brain power that it took to defeat the Nazis.

- Discovering a top secret Nazi code machine underwater

is definitely unusual.

So is what this next guy finds inside his fireplace

40 years after World War II.

- In Surrey, England, in 1982,

David Martin is doing a home renovation

when he discovers a bird skeleton in his chimney.

- As Martin removes it,

he notices a tiny red canister attached to its leg bone.

- Inside is a handwritten coded message

with the words "Pigeon Service" written at the top.

It was a tiny piece of paper with 27 separate coded messages

consisting of a very complex series of letters and numbers.

- [Narrator] But how did this pigeon

end up in Martin's chimney?

- This is a carrier pigeon

that was part of an elite avian communication service

during World War II.

- Pigeons were used to carry messages

between England and mainland Europe.

They were more reliable than secret radio transmissions

and they didn't put human lives at risk.

- The reason why pigeons are reliable

is because they're born

with these incredible homing instincts.

- Military training was used to teach baby pigeons

how to more accurately home

and navigate over greater distances,

from up to 1,000 miles away.

- They were so effective

the Germans even developed a squad of hawks

to take pigeons out

and even stationed troops along the coast with guns

to fire at pigeons as they flew by.

- [Narrator] Martin's pigeon is one of 250,000

who served during World War II.

- Martin immediately reaches out to British authorities

to report his find.

- But this is in 1982

and the British are fighting a war against the Argentinians

down in the Falklands,

so they have more pressing needs at this time.

- [Narrator] It's not until 2012 that Canadian researchers

are finally able to crack the secret code

this pigeon was attempting to deliver.

- According to them,

it was sent in 1944 by a sergeant, William Stott.

He's a paratrooper, dropped into Normandy before D-Day.

- What they think the message actually says

is revealing German positions there in Normandy

prior to the D-Day assault.

- The pigeon was probably on route to Bletchley Park.

It's just a few miles from Martin's house

and reportedly had a pigeon roost,

which would be home base

for the Pigeon Service in the United Kingdom.

- [Narrator] So how did this secret pigeon agent

wind up in a chimney?

- What they surmised is the pigeon was either shot or ill

and he finds his way into Martin's chimney

and that's where he ultimately passes,

dying in the line of duty.

- Over the years,

the Dickin Medal, Britain's highest award for animal valor,

was awarded to 32 war pigeons.

They even have a war memorial in London

that includes pigeons,

and that memorial has the greatest epitaph I've ever seen,

and it says, simply, "They had no choice."

- We've all stumbled across

an accidental find right in front of us,

but imagine making an incredible discovery

250 miles above the Earth.

[mysterious music]

- Mike Hopkins is an American astronaut

on the International Space Station,

and from that vantage point,

he's got this spectacular view of the Earth.

- Suddenly, his crystal clear view

is obscured by what looks like an ominous cloud

forming in the Earth's atmosphere over Russia.

So Hopkins grabs his camera and takes a photo of it,

then posts it on social media.

- [Narrator] The internet quickly erupts

as people everywhere try to figure out

what the strange cloud is.

- The place where the cloud showed up

was an area known as Kapustin Yar.

- This top secret military base is built in the 1940s.

It's 600 miles south of Moscow

and its construction is done under Soviet decree,

under the rule of Joseph Stalin.

Kapustin Yar becomes the research and development center

for Soviet technology during the Cold War.

There are even nuclear tests at the site.

- [Narrator] But Kapustin Yar may be hiding

more than Russian military secrets.

Some say it's the site of mysterious UFO activity in 1948.

- As the story goes, MIG pilots observe

a cigar-shaped unidentified flying object

and engage it in a dog fight,

and the result is that both aircraft go down.

The wreckage is then taken to Kapustin Yar.

- Interestingly enough, it's been called Russia's Area 51

and not without good reason.

- [Narrator] People wonder, could Mike Hopkins' photo

be evidence of another UFO over Kapustin Yar?

- Turns out Mike Hopkins wasn't the only one

to snap a picture of this strange cloud.

Another astronaut, Italian Luca Parmitano,

also took one and he posted a day later.

From his angle, it seems to show a vapor trail of a missile.

- [Narrator] As these photos go viral,

an independent website based in Geneva takes notice.

- The Swiss track Russian nuclear activity,

so they keep a close eye on Kapustin Yar,

and they discover that on that day,

the Russians carried out a confidential test launch

of a Topol SS-25 missile.

[missile booms]

- [Narrator] As global curiosity grows,

the Russians finally release a statement.

They say the rocket was used

to test new combat payloads for missiles.

- Hopkins didn't capture alien activity,

but what he did document was a top secret missile launch

from one of the most top secret facilities

in all of the Russian Federation.

- The Russians aren't the only ones with nuclear secrets.

Consider what an earthquake reveals in China.

- In May 2008,

[earthquake booming]

a 7.9 magnitude earthquake

rocks the Sichuan area of China.

The earthquake kills 90,000 people

and captures the attention of the world.

- Rescue crews aren't the only ones

racing to the disaster site,

so are radiation experts.

- And so when photographs show concrete tunnels

cutting through the collapsed mountainside,

it raises a few questions.

- [Narrator] What are Chinese radiation experts investigating

near strange, manmade tunnels?

A Georgetown professor named Philip Karber

wants to find out.

- He's not just a professor,

he's a former Pentagon official

and he works as a security consultant

for government agencies and private corporations.

- He's determined to get to the bottom

of what's happening below the surface in China,

so he turns to his Georgetown students.

- [Narrator] Over the next three years,

Karber and his team dig deeper,

researching the tunnels and the Chinese nuclear program.

- Karber knows that, historically,

first under Mao in the nineteen sixties

and then under Deng Xiaoping in the 1980s,

the Chinese tried to leverage

their relatively small nuclear missile force

by hiding it underground and in tunnels.

- [Narrator] Could these photos be evidence

that Chinese are expanding their nuclear capabilities?

Karber and his students are eager to find out,

but investigating underground tunnels

from 7,500 miles away is challenging.

- Karber and his students can't just go to China

and look for these tunnels,

so they have to get creative in their tactics

and where they can find the information.

- Karber turns his home

basically into a poor man's version of the Pentagon.

He purchases computers and flat screen monitors

and basically turns his house into a research facility.

His basement doubles as sleeping quarters

for these students who are burning the midnight oil.

- Karber returns to open source material,

looking at basically commercial satellite image of China

and television reports

to try to pick out any details they can

that might be relevant.

- Karber and his team are scrutinizing images

as closely as possible.

They identify a vehicle similar to a missile train.

They also see what they think might be

masked passenger cars,

known to transport long range missiles.

- [Narrator] Putting the clues together,

Karber and his students suspect

that these mountains are used to hide an alarming secret.

- Karber's team thinks that the Chinese have 3,000 warheads.

That's like more than 10 times the normal estimates.

That puts them in a league with the United States.

Suddenly thanks to Karber's research,

China has to be reassessed as a threat.

- [Narrator] The report from Karber and his students

rocks Washington.

- Word of the findings spreads

through the halls of power in the Pentagon

and eventually there are calls

for a congressional investigation.

This ignites heated debate

amongst intelligence and security experts.

- [Narrator] For years, many officials remain

skeptical of Karber's report,

but over a decade later,

the US government seems to support his findings.

- In 2023, the Pentagon reports

that China has thousands of these underground facilities

and are building more every year.

They're a key element of China's defense

and they enable them to hide military equipment

that they don't want to be seen by prying eyes.

And they're all revealed

with the help of a natural disaster.

- Sometimes a big discovery is just a phone call away.

Take one call during the Cold War

that turned up an incredible secret.

[thunder booms]

- It's April 22nd, 1956,

and a team of workers are looking for

an underground phone cable in East Berlin.

- It's been pouring rain for days,

the ground is completely saturated,

and the phone lines have gone down.

- It's thought that this may be

because of a short and a wire that's underground,

and so a team of workers are dispatched

to start digging for the faulty wire.

- So it's two in the morning

and these guys are out there with their shovels,

and they're digging and they're digging,

and they're hoping to find cables

so they can fix the problem,

but they find something else.

[pickaxe clinks]

- [Narrator] They hit concrete that isn't supposed to be there.

- The workers can't help but be curious,

so they crack open a small hole and they look inside.

- To their amazement, they found an underground room

full of high tech equipment.

The workers notify their superiors

and when they investigate, they find that there's a tunnel

connecting communist East Berlin

to American, British and French controlled West Berlin.

- [Narrator] What the men have discovered

is a joint CIA and British Intelligence project

called Operation Gold.

- Operation Gold began about two years earlier

when American and British forces wanted to figure out

a way to eavesdrop on conversations

that were happening in East Berlin.

The British and the Americans build this large warehouse

on their side of Berlin,

but to use the language of the intelligence community,

it's a cardboard cutout; it's a cover.

This warehouse was actually built to hide

the entrance of a secret tunnel

that granted them access

to those East German and Soviet cables.

- This tunnel is a quarter mile long

and it's filled with the latest communications technology.

What they're able to do is end up in communist territory

just below telegraph and telephone wires,

which allows the Allies

to tap into East German communications.

- By the time that the covert plan is uncovered,

the CIA has already amassed

40,000 hours of recorded conversations

and they have compiled 1,750 intelligence reports

based on those tapes.

- This is a windfall of Soviet secrets for the West,

covers everything from group movements,

to the names and identities of key players

in the atomic and intelligence programs,

to the location of military bases throughout Europe.

- [Narrator] It all comes to a crashing halt

when these workers find the tunnel

and the Soviets waste no time

turning the discovery into a propaganda bonanza.

- So in finding this,

the Soviet Union can frame themselves

as victims of American espionage.

They bring the press in and they show them this tunnel,

and they show them all the communication equipment

that the Americans have put in here

to eavesdrop on Soviet communications.

And this story makes headlines around the globe.

- [Narrator] Five years later,

this story takes an unexpected turn.

- In 1961, the British arrest

one of their own intelligence agents, George Blake.

As it turns out, he was a double agent

who was feeding intelligence information

to the Soviets for years.

- While in custody, Blake confesses to having shared

secrets about Operation Gold with the Soviets

years before the tunnel was built.

- [Narrator] So if the Soviets knew about the tunnel,

why didn't they say something sooner?

- The Soviets realized that if

they were to expose the tunnel,

they would lose their double agent Blake

because the leak would immediately

be traced back to him.

- He's providing the Communists and the Soviet Union

a treasure trove of classified and top secret information.

And so if they watch what they say,

they're not gonna tip their hand

because they know that the Americans are listening.

- [Narrator] But in 1956,

the Soviets decide to use their find as leverage.

- Now, Khrushchev,

who's premier of the Soviet Union at this time,

has plans to visit the West

and he has this information in his back pocket,

and he plans to use it

to make a big splash in the Western press.

- So the Soviets come up with this story about the bad cable

to justify sending out a team

to begin digging and thereby discover the secret tunnel.

This cover story doesn't just preserve Blake's identity,

it also gives Khrushchev exactly what he wanted,

something to hold over the West's head.

- [Narrator] In other words, this accidental find

is not so accidental after all.

- There never was any issue with the telephone wires.

The Soviets sent these unsuspecting workers out

knowing full well what it was that they would find.

- The discovery was just a cover story

in this Cold War chess match

that pitted the East against the West.

- Back before smartphones, we had to hand write directions

to get to where we wanted to go.

That leads one man to some place surprising.

- Journalist Garrett Graff is at his desk

and he's starting his day,

but then something strange happens.

One of his coworkers puts

a US intelligence agency badge on his desk.

- The colleague had found the badge

lying in a parking garage

and he thinks that Graff,

since he knows people in that sphere,

might be able to return it to his rightful owner.

- Graff examines the badge

and notices on the back, the words,

"long-term evacuation directions"

followed by driving directions.

He's instantly intrigued,

not so much by who the badge belongs to,

but where these directions might lead.

- Graff ends up driving 130 miles to West Virginia,

but the directions don't lead him to a military base

or a government facility,

but instead to the side of a mountain.

There's a chain link fence and behind that, concrete doors.

It's like something straight out of the movie "War Games."

- What Graff realizes is

the directions that were in the back of this badge

has taken him to a top secret US bunker.

- [Narrator] Graff knows that government bunkers

were built in the 1950s and '60s

to protect important officials during the Cold War.

But strangely, this bunker appears to be much newer.

- Eager to learn more,

Graff buries himself in recently declassified documents,

conducts interviews with people

who have been inside these bunkers,

and visits military facilities around the country.

- Eventually, he discovers

the kind of crown jewel of those shelters,

a base known as Raven Rock.

- Constructed in the 1950s,

Raven Rock is nestled in the mountains

of Pennsylvania's southern border.

It's referred to as the underground Pentagon

because in the event of a nuclear attack,

the Pentagon would transfer to Raven Rock.

- These continuity of operations plans

do involve taking senior US government officials

out of Washington

and taking them to classified areas

where they would continue to ensure that

the process of government of the United States continues.

I'm very confident that this is true

because back when I was secretary of the Air Force,

I was one of those people.

- This is an entire city

entombed underneath a quarter mile of granite.

So it runs 24/7, 365 days a year.

It has police and fire departments,

it has a chapel, a dentist, a cafeteria,

it's a complete city.

- When it opens, it's about the size of a city block

and it can house up to 1,400 people for a full month.

- [Narrator] By the start of the 21st century,

these bunkers and plans to survive a nuclear attack

seem to be nothing more than Cold War leftovers,

until September 11th, 2001.

- The terrorist attacks

put the safety of government officials

back in the spotlight.

- Graff discovered that in the aftermath of the attacks,

important government officials,

supposedly including Vice President Dick Cheney,

were taken there for safety.

- Although I am not at liberty

to discuss classified information,

I can assure you that the United States has

a very robust plan for continuity of operations.

- And what Graff finds out is that Raven Rock

undergoes a number of significant renovations.

In 2001, the complex included 59 buildings.

- By 2013, the facility expands to 66 buildings.

So in the event of an emergency,

it can serve as a safe house for over 3,000 people.

- Who would've thought that something as simple

as a lost government ID badge

would pull back the curtain on some of America's

most closely guarded secret spaces?

[mysterious music]

- You don't have to be a spy

to uncover a big military secret,

but what you do discover could be a game changer.

I'm Danny Trejo,

thanks for watching Mysteries Unearthed.