Original subtitles

[dramatic music]

[Duchovny] Tonight on "Secrets Declassified"...

government projects so daring or so dangerous,

they're hidden underground,

like an experiment to hide a nuclear explosion

under a Mississippi forest.

- The effects are immediate, and they are dramatic.

What did they expect? It's a nuclear bomb.

- Or a high-stakes mission to spy on the Nazis

by hiding British soldiers inside the Rock of Gibraltar.

- The entrance will be bricked up.

No one will be allowed to leave

under any circumstances.

[David] Even a military experiment

on the New York subway.

- Just five minutes after bacteria are released,

spores are detected at every station

between 14th Street and 59th.

- These are the astonishing and sometimes terrible things

done by governments and the people who work for them.

It's time to bring them to light.

♪ ♪

The thought of being buried alive in a sealed-off cave

would strike most people with terror.

In World War II, six British officers

volunteered to do exactly that on the Rock of Gibraltar.

[crowd chanting in German]

[Sami] In 1941, it seems like Hitler is winning the war.

Europe has fallen, but Britain maintains the naval advantage.

♪ ♪

Key to its success is a peninsula

on the southern tip of Spain known as Gibraltar.

[David] Although it's small,

Gibraltar has been one of Britain's

most important overseas outposts

for over two centuries.

[James] This is because it's strategically important.

It guards the only gateway

between the Mediterranean and the Atlantic seas.

[Martin] From the Rock of Gibraltar,

1,400 feet above the water level,

an observer is in a perfect position

to note the comings and goings of ships

entering the Mediterranean or departing the Mediterranean.

♪ ♪

[Duchovny] The rock is so vital,

Hitler plans to seize it.

For Britain, it's unthinkable.

And one naval officer is called to action.

- John Godfrey is Britain's Director of Naval Intelligence.

What he realizes is that British forces

are unlikely to repel a German assault on Gibraltar.

♪ ♪

[Duchovny] Losing the rock could mean losing the war.

So Godfrey devises a last-ditch plan,

which will remain classified for over 50 years.

[Sami] He decides to build a secret hiding place

inside the Rock of Gibraltar.

So, when the Germans attack,

a small crew of officers will seal themselves inside

and continue to monitor the shipping lane,

even after the rest of the British forces

have been defeated.

[David] It's a truly bold idea.

Godfrey codenames it Operation Tracer.

His first challenge--

finding the perfect hiding place.

- Gibraltar has been used as a military outpost

for 250 years.

Carved into the rock is a maze of tunnels and chambers.

[David] Godfrey's team

locate a closed-up section of tunnel

in an abandoned part of the rock.

- It's perfectly positioned--

high up and overlooking both sides of the rock,

east towards the Mediterranean, west towards the Atlantic.

So the spies can monitor movements of German shipping

in both directions.

[David] It's got a great view.

But to make it habitable,

they must give it a radical renovation

without giving away

the tunnel's secret location to anyone.

- Secrecy is paramount, so workers are blindfolded

when they're brought to the location

and then shipped back to Great Britain

upon completing the job.

[Duchovny] The top secret bunker they carve out

is truly remarkable.

[O'Keefe] The living quarters include bunk beds,

a chemical toilet a 10,000-gallon water tank.

[James] There's a small radio room

so that they can transmit their intel back to Britain.

They actually have a radio antenna

that can be poked through a hole in the rock face

under the cover of night.

Now, electricity for the radio

will be produced by using a bicycle

rigged with a silent leather belt,

which doubles as the men's only form of exercise.

[David] The most extreme feature

of this underground safe house...

there's no way out.

- The men won't just be hiding in this bunker.

The entrance will be bricked up,

and they will be sealed inside.

No one will be allowed to leave under any circumstances.

♪ ♪

- Staying inside is so crucial

to the mission's success

that one corner of the bunker

is reserved to be used as a cemetery

should any of the officers die on the job.

- For the volunteers, this mission is the end of the line.

I think if Gibraltar falls,

they're saying goodbye for good.

♪ ♪

[Duchovny] For Operation Tracer to work,

Godfrey needs help finding the right men.

So he turns to an expert in extreme survival.

♪ ♪

[James] George Murray Levick is quite the character.

He's an explorer who once survived a whole winter

in Antarctica by living in an ice cave

and eating penguin meat.

- Levick scours the navy

and eventually selects six officers.

[Duchovny] To see if they can survive in the bunker,

Levick puts them to the test.

- The men live in an isolated hut

on a remote marsh for weeks.

[Duchovny] To prepare for life underground,

one final sacrifice is required...

♪ ♪

Surgery.

- All of the men have their tonsils and appendix removed.

And this is done to reduce the possibility

of them developing a life-threatening infection

during the mission.

- Once they pass their training,

their reward is to go home, see their families,

and say goodbye.

♪ ♪

[Duchovny] In the summer of 1942,

six British naval officers are shipped to Gibraltar

with top secret orders.

- The men are placed in Gibraltar under cover

of regular military postings.

But in secret, they sneak off and run checks

on the secret bunker,

always waiting for that order that will seal them inside.

♪ ♪

[Duchovny] But the order doesn't come.

The German march across Europe never reaches Gibraltar.

And the secret bunker is permanently sealed up

with nobody inside.

♪ ♪

- The bunker is quickly forgotten about.

It becomes a footnote to World War II history.

[Duchovny] Operation Tracer remains a secret for 50 years,

until a chance discovery in 1997.

♪ ♪

[James] A team of cavers

exploring Gibraltar's vast underground labyrinths

find a mysterious sealed-off bunker.

They believe they've stumbled

across the legendary Operation Tracer cave.

[O'Keefe] One of the original volunteers

confirms that this was really the place

that he was prepared to die in.

♪ ♪

[Duchovny] Rumor is, the British government

has other stay-behind caves across the world,

waiting to be deployed.

♪ ♪

Burying people underground is one thing,

but in 1964,

the U.S. government tries to bury something

a little more ambitious--

a nuclear explosion

right in the middle of America's heartland.

♪ ♪

[Hakeem] By the early 1960s,

there has been something like 500 nuclear tests

that have taken place in the Earth's atmosphere

around the world.

And there's been a buildup of public anger and concern

about what damage these tests have done.

So the U.S. and the Soviets reached the first agreement

to limit nuclear testing.

[Duchovny] But this historic treaty has one giant loophole.

It forbids nuclear tests in the atmosphere,

outer space, and underwater...

but not underground.

♪ ♪

- The reason underground nuclear testing remains legal

is simply because no one knows how to detect

and therefore police it.

And a ban can only work if you can verify

that people are breaking it.

- As far as the U.S. is concerned,

the Soviets might be exploding nuclear devices

under the Arctic waste, and they are none the wiser.

♪ ♪

[Duchovny] U.S. officials are desperate to know

if nukes can be covertly detonated underground.

There's only one way to find out.

- In 1963, the American Atomic Energy Commission

decide to conduct a series of underground nuclear explosions

to see if and how they can be monitored.

♪ ♪

[Duchovny] The operation's code name

plays down the potential for Armageddon--

Project Dribble.

Its first challenge--

find the best hiding place for a nuclear explosion.

- The scientists working on the project theorize

that the most effective environment

to conceal an underground test would be in a salt dome.

[Dan] Salt domes are geological formations

deep under the Earth's surface where rock salt

has risen up to form a dome-like structure.

And those domes of salt

can be 6 miles deep.

[Martin] The thought was that the salt dome would have

the effect of containing the force of the explosion.

And it was also thought then, too,

that the fallout, the radioactivity

that was produced by these explosions,

would remain inside the salt dome

and would not be hazardous to people aboveground.

♪ ♪

[Sasha] And they find this ideal patch

underneath a pine forest

in Lamar County in southern Mississippi.

It's called the Tatum Salt Dome,

and it's about 1,500 feet under the surface.

♪ ♪

The one catch is a nuclear test

might not go down well with the local population.

[Hakeem] Mississippi is not the Nevada desert,

where the U.S. has typically tested their weapons.

[Dan] This salt dome is close

to the town of Hattiesburg, Mississippi,

and is by far the most densely populated atomic test site

the U.S. has ever chosen.

[Duchovny] Fearing local protests,

the government decides to promote the positives

of living near a nuclear test site.

- Mississippi's governor assures the residents,

everything's gonna be okay.

That salt dome, that's going to hold in the radiation.

It's going to protect them.

And more than that-- it's important to do so.

This is how Mississippi contributes.

It does its small part for Uncle Sam

to fight against communism.

♪ ♪

[Duchovny] In the fall of 1964,

the operation to explode a nuke

under Mississippi begins.

- The U.S. atomic scientists create a shaft

that's half a mile deep.

And into it, they put down a device

with a yield of 5.3 kilotons.

That's about a third the yield of the device

that was dropped on Hiroshima.

They fill the borehole with concrete,

and then they place scientific devices around the area

to record seismic waves and measure any radiation

that may leak into the atmosphere.

- Nobody really knows how this test will go down.

So about 400 people are evacuated as a precaution.

Adults are paid 10 bucks for the inconvenience,

and kids are paid half.

[Duchovny] On October 22nd,

the scene is set for the nuclear detonation

inside the salt dome.

♪ ♪

Will it be truly undetectable

or split the Earth apart? [siren wailing]

- One of the strangest nuclear tests on American soil

happens under Mississippi in 1964.

Scientists want to know,

can you detonate a nuclear bomb underground

and hide it from the world?

[siren wailing]

On the morning of October 22nd,

the local residents find out.

[wailing continues]

[explosion]

- The explosion carves out a huge cavity

deep inside the salt dome.

The ground lifts.

A shock wave ripples across the landscape.

Small buildings collapse.

Homes are severely damaged.

Wells suddenly go dry,

and some creeks start to run black with silt.

[Duchovny] Locals file hundreds of damage claims

almost immediately.

But for Project Dribble,

the test results are priceless.

- It sends waves, seismic waves out 5,000 miles.

Finland picks up the fact

that this test was done in Mississippi.

Clearly, while the test has done its job,

it's demonstrated that, in fact,

there's no way the Soviets are doing any underground testing.

♪ ♪

[Duchovny] A happy ending for the U.S. government

but not for the locals living near the salt dome.

♪ ♪

- A lot of residents start reporting illnesses.

Soon, cancers and birth defects start to show up--

all symptoms that locals believe

are caused by nuclear contamination

from the salt dome tests.

♪ ♪

[Duchovny] The Atomic Energy Commission

claims the site has successfully contained

the radiation

and illness rates in the region are normal.

But in 2015, a local journalist

requests official information regarding payouts

made in the aftermath of the nuclear test.

- By the early 2000s,

the federal government has paid out

about $16 million in settlements

to people that were exposed to radioactivity

as a result of Project Dribble.

[Duchovny] What began as a step towards nuclear control

remains a source of anger for the local community

that continues to this day.

♪ ♪

While many Nazi officers end World War II on trial,

one German spymaster plans to secure

his postwar future

by trading a cache of buried secrets

for his freedom.

♪ ♪

[Don] In early 1945, the German army is crumbling

and outnumbered on all fronts.

The collapse of the Third Reich looks inevitable.

So many of the top Nazi commanders

shift their focus from winning the war

to surviving the collapse of the Nazi regime.

♪ ♪

[Duchovny] One German fearing for his life

is Reinhard Gehlen.

- Reinhard Gehlen is the Nazi Head of Military Intelligence

on the Eastern Front,

where the Germans are fighting the Soviets.

He's been running a network of spies

in Soviet territory for years.

Gehlen has files

on all the Soviet Union's dirty secrets.

And if the invading Russians get a hold of him,

he could be spending the rest of his days

in a Siberian gulag.

That's if they let him live.

♪ ♪

[Duchovny] Gehlen spots one potential escape route.

- Gehlen sees what many others don't,

which is that after the war,

the Soviets and the United States

will be rivals, not allies.

- He knows that the Americans

are going to be interested in what he knows about Russia.

[Duchovny] Key to Gehlen's survival

is his archive of Soviet secrets.

- This is his bargaining chip.

This is his get-out-of-jail-free card.

♪ ♪

[Duchovny] Gehlen has to think fast.

His solution...

hiding his files underground.

- He's going to go bury his treasure like a pirate

and then go work out his deal with the Americans.

[Duchovny] Burying an entire archive

is no easy task,

especially in the dying days of a global war.

- First, Gehlen asks his staff to begin the mammoth task

of transferring his files onto microfilm

and then storing them in watertight steel cases.

Over 4 days, they fill 50 cases with priceless treasure.

- But he realizes that the best place to secure these documents

would actually be all the way down

by the border between Germany and Austria,

down in the Bavarian Alps.

So he's going to travel 300 miles

to bury his documents

and hopefully hash out a deal with the Americans.

♪ ♪

[Duchovny] In early May 1945,

Gehlen and his staff skip town

in a truck loaded with secrets

and head for the Alps.

- Gehlen and his party reach this isolated forest hut

in a remote valley.

♪ ♪

He decides to bury his cases here

before the Americans can catch him.

♪ ♪

- To avoid the possibility that the entire archive

is discovered or destroyed, he splits the cases

and buries them in eight different spots.

♪ ♪

[Don] Then Gehlen waits...

for a month in the Bavarian wilderness,

until American forces arrive in full and he can surrender.

[camera shutter clicks]

♪ ♪

[Duchovny] Gehlen is sent to an interrogation center,

where he is questioned by a U.S. Army officer

named Captain John Boker.

[Sami] The meeting with Boker is a make-or-break moment.

Gehlen has just one opportunity to play his hand.

And luckily for him, Boker shares his view

that the Soviets are a threat to the United States,

and he wants to know everything that Gehlen knows.

- The United States didn't have a lot of information

about the Soviet military.

Someone like Gehlen was the goose

that could lay golden eggs.

♪ ♪

- Captain Boker can't just strike a deal

with a high-ranking Nazi official,

at least not without knowing he's for real.

He needs to dig up Gehlen's buried secrets.

- So he assembles a team that's going to essentially follow

the treasure map, if you will,

and head on out to the cabin.

And they find exactly what Gehlen's described.

They are able to dig up in the spots

where he said he buried the documents,

and they find seven out of eight of the deposits.

[Duchovny] Gehlen delivers on his word.

In return, Boker removes Gehlen's name from the system.

- Gehlen is not listed officially as being a POW.

- Gehlen has played his cards perfectly.

The Americans aren't going to arrest him.

They're gonna use him as an asset.

[Greg] So Gehlen flies out to Washington, D.C.

And working with the Americans,

he strikes an astonishing deal.

He's going to return to Germany

to lead a covert agency that's spying on the Russians.

[Duchovny] While other Nazi leaders face trial

for war crimes,

Reinhard Gehlen returns to West Germany.

He reconnects with his old network of spies,

and they continue their operation,

not for Nazi Germany

but for the United States.

- For the next 23 years, Gehlen's organization

is the number-one supplier of Soviet secrets.

[Duchovny] Gehlen's vital importance

to U.S. intelligence agencies stays classified,

until the year 2000.

♪ ♪

55 years after the Nazis were defeated,

the CIA releases thousands of files

detailing their relationship with Gehlen...

a partnership that grew from a trove of secrets

buried in the mountains.

♪ ♪

- For millions of New Yorkers,

heading underground is part of everyday life.

But in 1966, what seems like a regular morning commute

is actually part of a secret military experiment,

where passengers catch more than a ride to work.

♪ ♪

[Dan] In the 1960s, New York City's subway

is the busiest transport system in the United States.

At rush hour, millions of Americans

are using it to crisscross the city.

The U.S. military is worried

that this incredible feat of engineering

is also an Achilles' heel in the nation's infrastructure.

It might be a weak point vulnerable to attack

from America's enemies.

♪ ♪

[Duchovny] There's one specific kind of warfare

that has the U.S. Army on high alert.

- At this point, both the United States

and the Soviet Union have bioweapons programs.

American officials are worried that the New York subway system

would be a prime target for an attack.

Not only does it move millions of people every day,

it moves them throughout the city,

potentially spreading a virus easily

throughout the whole population.

[Duchovny] It's a doomsday scenario

the U.S. Army wants to prepare for.

So they decide to conduct a chillingly named

"vulnerability assessment."

[Don] In 1966, U.S. Army scientists

conduct a mock bioweapon attack on the New York subway system.

Their plan is to release an airborne bacteria

named Bacillus subtilis

that is considered harmless to humans,

then monitor its spread through the subway.

♪ ♪

[Duchovny] Safe or not, New York commuters

might object to inhaling unknown bacteria.

So, to sidestep the thorny issue of consent,

the U.S. Army decides to run this experiment in secret.

- At the time, the Army decided to just go forward anyways.

And they didn't tell anybody, no local authorities,

not even the transit police.

[Duchovny] On June 6th,

21 Army scientists disguised as everyday commuters

head underground

to stations along the 7th and 8th Avenue lines.

- To deploy the bio agent secretly,

each operative carries special light bulbs

hidden inside boring-looking paper bags.

Packed inside each of those light bulbs

is a gas inoculated with 175 grams

of Bacillus subtilis bacteria.

That's about 87 trillion organisms

in each bulb.

- The scientists wait on the platform

for the train to come.

When the doors open, they walk inside,

and they discreetly drop the light bulbs

in between the train and the platform.

The glass shatters on the tracks,

and the bulb releases its contents.

And with each passing train,

the bacteria gets pulled through the tunnel

to the next station.

[Dan] From what's been pieced together,

it appears that some commuters did notice clouds of gas

rising up from the tracks.

But there are no descriptions of widespread panic.

These people just brushed off their clothes

and went on with whatever they were doing that day.

For millions of commuters,

it just felt like a normal Monday morning.

[Duchovny] With the bacteria

now silently passing through Manhattan,

the scientists secretly track it

through dozens of miles of underground tunnels.

- To monitor the air and trace the bacterium,

the scientists have devised these clever covert gadgets

that can take readings without passengers noticing--

air samplers disguised as cameras,

detection devices hidden in pocketbooks.

♪ ♪

- For five days, millions of commuters

remain completely unaware of the experiment.

When results are tallied, the conclusion is horrifying.

♪ ♪

[Don] They show that just five minutes

after bacteria are released at the 23rd Street Station,

spores are detected at every station

between 14th Street and 59th.

- According to military calculations,

more than one million Americans were exposed to the bacteria.

So, if that had been anthrax, with a million people exposed,

the math is not complicated.

Anthrax is 90% to 97% lethal.

It would have been an unmitigated disaster.

- The Army's conclusion is stark.

The subway system cannot be safeguarded

against this type of attack.

It would put New York out of commission.

[Duchovny] For nine years,

New Yorkers remain unaware they have been subjected

to a bioweapon experiment.

♪ ♪

Then in 1975, the U.S. military

is dragged in front of the Church Committee

to answer questions on illegal or unethical activities.

♪ ♪

One of the skeletons they bring out of the closet

is the New York subway vulnerability test.

♪ ♪

The most frightening revelation is still to come.

- The bacterium the scientists used, Bacillus subtilis,

isn't as benign as they thought.

It can be a harmful pathogen.

It can cause lung infections, meningitis, even death.

And people with weakened immune systems

are especially vulnerable.

- At the time, the scientists don't do any research

into the physiological effects of the test

because they assumed it was safe.

But it's highly likely this attack wasn't just unethical

but physically harmful, too.

- When German bombs rained down during World War II,

London's most vulnerable residents are rushed to safety.

Children are sent to the country,

while priceless works of art are sent underground.

[dramatic music]

[bell tolling]

[Don] At the start of World War II,

the UK's National Gallery holds one

of the world's greatest collections of art,

including over 2,000 masterpieces.

This is not just a collection of cultural significance.

We're talking tens of billions of dollars.

[Duchovny] The gallery's director,

esteemed art historian Kenneth Clark,

is determined to save these paintings

from the incoming blitz of German bombs.

- Clark's first priority is to get all the paintings

out of London as quickly as possible.

And he does this in an ingenious way.

They're hidden in post office vans

and Cadbury's Chocolate delivery trucks,

and they're transported

to a number of remote buildings in Wales.

Now, the government believes

that it's here in western Britain that they're gonna be

safely out of range of Luftwaffe bombers.

[explosions, sirens wailing]

[Duchovny] But they are wrong.

[O'Keefe] In September 1940, the Blitz begins.

By November, the German Luftwaffe

have hit targets in Liverpool, which is north of Wales.

It becomes apparent

that the Germans can hit any target

throughout mainland Britain.

[Duchovny] These priceless paintings

could be erased in a moment.

They have to be moved.

- Churchill wants to keep them in Britain, announcing...

[imitating Churchill] "Not one picture shall leave

this island."

[normal voice] So Clark must find a bomb-proof solution.

And he decides the safest place is underground.

- It must be remote and secure, accessible by road and rail,

and, most importantly, suitable for housing delicate artworks.

[Duchovny] The National Gallery

launches a covert sweep across Britain

to find the ideal underground vault.

And in late 1940, they strike gold--

or rather slate.

[Greg] In a windswept valley

near one of Britain's tallest mountains out in Wales,

they find Manod Quarry,

which was a slate mine back in the 1800s.

It's no longer in use,

but it's got all these carved-out chambers

deep down underneath hundreds of feet of slate...

natural defenses that should be able to keep

this art safe and sound.

[Duchovny] With the clock ticking,

the UK government secretly rents the mine.

But the art collection can't be rushed in overnight.

- You can't just stick paintings in a wooden crate

and bury them in an old mine.

They are highly sensitive

to all sorts of environmental damage.

- If they're going to keep these paintings safe,

they're going to need to manage the environment.

Otherwise, one of the greatest art collections in the world

won't be destroyed by bombs, it'll be destroyed by mold.

[Duchovny] Deep inside Manod Quarry,

a state-of-the-art storage facility

is constructed.

[Amy] Six airtight brick bungalows are built

right in the heart of the mine to protect the paintings.

To protect them against dust and damp,

a series of electric fans are installed.

These fans pass air over trays of silica gel

that absorb all of the ambient moisture.

This keeps the moisture level in the mine in check.

- After a six-month breakneck renovation,

the secret vault is ready

to welcome its first masterpieces.

♪ ♪

[Don] The collection is transported

by covert convoy deep into this Welsh mountain,

all in total secrecy.

Only a handful of officials know where it's gone.

[Duchovny] There's just one slight oversight.

- Some of this art is enormous.

Van Dyck's painting of Charles I

measures 12 feet in length.

So, as the truck carrying it

is winding through these small roads,

there's a low bridge that these trucks have to pass under.

Well, Charles I is too big to make it underneath.

They have to lower the road that's going

underneath this bridge just to get Charles to safety.

[explosions, sirens blaring]

[James] Back in London,

the Blitz continues to cause carnage.

The National Gallery ends up being hit nine times,

but its prized assets--

well, they're safely tucked away under a mountain.

♪ ♪

[Duchovny] One of the world's most important art collections

narrowly dodges incineration.

But Manod Quarry doesn't just protect the paintings,

it improves them.

- The conditions in the mine are so good,

the paintings actually fare better than if they'd been left

in the National Gallery.

- When the war is over, when it's finally time

to return this art back to the National Gallery,

they actually bring with them

what they've discovered and learned

about painting preservation.

[Duchovny] The National Gallery

reopens to the public on May 17, 1945.

But the mountain vault is kept secret

long after the war is over.

The full story of Manod Quarry is buried for 78 years.

♪ ♪

[Don] Back in 2018, the National Gallery

mounted an exhibition revealing photos and documents

from inside the quarry for the first time,

unveiling the extraordinary tale

of ingenuity and secrecy

that saved this priceless collection

from obliteration.

- It's the Cold War,

and underground nuke-proof bunkers are all the rage.

Every world leader has one.

For Stalin, though, protecting his government is not enough.

He wants a shelter big enough for his submarines.

[tense music]

♪ ♪

[Hakeem] By 1953, Stalin is growing incredibly concerned

by America's increasing nuclear arsenal.

And he fears that a single strike

could knock out a large part of his military,

in particular his submarines.

♪ ♪

At this time, the Soviet submarine fleet

is the largest in the world, boasting over 300 vessels.

And each one of these submarines

is worth over $10 million.

[Duchovny] Stalin wants his billion-dollar fleet

hidden away from prying eyes and safe from falling bombs.

[O'Keefe] Stalin orders something

that has never been attempted before--

a nuclear-proof underground stronghold

with a secret gate to let subs pass

into and from the ocean in total secrecy.

[Duchovny] To find a location for his super base,

Stalin turns to one of the few people he trusts--

Lavrentiy Beria.

♪ ♪

- Lavrentiy Beria is the head of the Soviet KGB.

He's in a position of great authority and power

and a confidant of Stalin's.

Stalin turns to Beria to identify a place

for a reinforced submarine base

that can survive a thermonuclear attack.

♪ ♪

[Hakeem] Beria and his team spend months

scouring the coastlines,

looking for an ideal location

that will afford maximum security

and natural protection.

They find a remote bay on the Black Sea

called Balaklava.

[Don] Balaklava is home to a twisting inlet

around 200 meters deep.

It's sheltered from storms, with a narrow entrance

that's impossible to spot from the open sea.

It's also just 9 miles

from the Soviet naval port at Sevastopol,

which houses Stalin's Black Sea fleet.

[Duchovny] The sheltered cove is perfect.

Now Stalin's team must dig out

one of the world's biggest nuclear bunkers

in secret.

- It's gonna take years to build.

And it's happening right around the corner

from a regular old fishing town.

So keeping it secret is gonna be a huge challenge.

- The Soviets immediately declare Balaklava is closed

and effectively remove it from the map.

Then they secretly bus in workers

to start building the facility.

[Greg] During the night, materials are brought in.

And during the night, debris that is being created

as they tunnel out a mountain is taken out.

Meanwhile, any entrances and ventilation shafts

are covered with netting.

This will protect the Soviets from any flyover surveillance

that might see what's going on.

♪ ♪

[Duchovny] It takes eight years

to extract nearly 120,000 tons of rock from the mountain,

carving out a Cold War marvel in the process.

- The finished base can hide 10 submarines,

including 7 in one central channel

that's 500 meters long.

It also includes a dry dock,

missile storage, command rooms,

and a power infiltration system--

all of it under 130 meters of rock

with 4.5-meter-thick concrete walls.

It's designed to withstand a direct nuclear-bomb strike

of up to 100 kilotons.

That's 6 to 7 times that of the Hiroshima bomb.

♪ ♪

[Don] It can be completely sealed

with a set of colossal underwater gates

made from 150 tons of solid steel.

They are 7 meters high, 10 meters wide,

and provide the final line of defense,

guaranteeing protection for the submarines inside.

- The most secure room in the heart of the complex

is where the nuclear warheads are stored.

The base isn't just designed to withstand an atomic blast.

It's fully prepared for retaliation.

- In the event of a nuclear war,

3,000 people can hide in here for up to 30 days.

♪ ♪

This place is virtually indestructible.

- Basically, it's something out of a Bond film.

[Duchovny] Despite extreme efforts to avoid detection,

rumors about the Balaklava base start to leak out.

- The area around Sevastopol is photographed.

The area of Balaklava is photographed.

[Duchovny] U.S. spies piece together

small fragments of intel,

but the base is so effectively hidden

that its full nature remains shrouded in mystery.

Only after the collapse of the Soviet Union

is this secret site deactivated.

- In 2003, this Cold War labyrinth

is open to the public as a museum.

For several years,

its tunnels echo with the footsteps of tourists

rather than military officers.

[Duchovny] But after Putin's invasion of Ukraine,

the base is back in the conversation.

And the rumors are, it's being reactivated.

- When the U.S. comes under attack on 9/11,

the government relocates to an emergency bunker

for the first time in history.

The only problem is, it's 50 years out of date.

[dramatic music]

♪ ♪

- In 1950, the White House is undergoing

a massive expansion.

President Truman is overseeing renovations of the East Wing.

Truman decides that in the atomic age,

the White House

needs a nuke-proof emergency shelter--

one to be used in the event of a Soviet attack on D.C.

[Duchovny] The $11 million investment under the East Wing

is called the Presidential Emergency Operations Center.

- The P-E-O-C, or PEOC, is an underground bunker

meant to protect the president and key personnel,

meant to ensure continuity of government

and also meant to act as a command and control center

in a time of crisis.

[Sami] It's accessible from an elevator in the East Wing.

Behind these heavy steel doors,

there's a shower room

for washing off any nuclear fallout.

This then leads to a number of rooms,

including a food store,

living quarters for the President and the First Lady,

and, most importantly, the communications center,

which has direct telephone lines to the Pentagon.

[Duchovny] Truman's PEOC is a cutting-edge hideaway,

ready and waiting for a threat to the White House.

But the threat never comes.

And for 50 years, it lies dormant...

until 2001.

- Oh, my God. Oh, my God.

♪ ♪

[Sami] When the Twin Towers are hit

and the United States is under attack,

President Bush is in Florida.

But the First Lady, Laura Bush, is in D.C.

♪ ♪

- Laura Bush was at the Congress.

She was at the Capitol.

[sirens wailing]

The Secret Service-- they sent her to the PEOC.

♪ ♪

[Duchovny] The secret bunker is called on

for the very first time.

♪ ♪

[Tim] Laura Bush had never been to the PEOC before.

She describes walking through a tunnel...

♪ ♪

going through these metal doors into the secure facility.

♪ ♪

Who was there but Vice President Cheney

and Mrs. Cheney.

- President Bush is in the air, flying back to Washington.

So the vice president is running things

from underground.

[Duchovny] The PEOC is suddenly

the most important room on Earth.

♪ ♪

- Immediately things start going wrong.

- Cheney can't get through to key personnel.

And there's another problem.

The TV screens can play live news programming,

but then they can't hear

the internal video teleconferencing.

♪ ♪

[Duchovny] It's not just the communications

that are failing.

[Sasha] There is an air problem.

The room is sealed, it's crowded,

and carbon dioxide levels are rising.

[Duchovny] With CO2 levels rising,

the evacuated staff start to feel the pressure.

[Sasha] The vice president has to choose.

He can either stay in the safety

of this subterranean bomb-proof shelter,

or he can go upstairs

into the unfolding chaos and take control.

♪ ♪

[Sami] Cheney is instructed to stay underground.

So he's in the failing operations center

for the whole day.

[Tim] The Bushes were asked by the Secret Service

if they wanted to spend the night there.

Neither one wanted to.

♪ ♪

It was a pretty crammed

and not terribly inviting place to be.

[Duchovny] The PEOC turns out to be a Cold War relic,

no longer fit for purpose.

The details of what happened down there are kept hidden

for nearly a decade.

[Sami] In 2010, Laura Bush publishes her memoir,

in which she reveals her experience

in the outdated bunker.

♪ ♪

[Duchovny] Just months later,

diggers start pulling up the White House lawn.

In the wake of the PEOC's failings,

a massive renovation project takes place underground.

♪ ♪

- A new and improved 21st-century operations center

is installed five stories below the White House,

so hopefully something like this never happens again.

♪ ♪

- From hidden experiments to buried bunkers,

governments have long concealed secrets deep under the Earth.

But no secret stays buried forever,

even the most surprising.

♪ ♪