Underground Marvels (2019–…): Season 2, Episode 5 - Ireland's Underground Alcatraz - full transcript

[narrator] In Ireland,

three coastal fortresses

created a covered military stronghold.

How was this strategic
defense hub designed to protect

against enemy attack?

And years after it's construction,

what new role did it take on?

It's hard to imagine a worse place

for a person to be kept.

[narrator] Buried in the remote
hills of Northern New Jersey,

a vast underground world



with an illuminating history.

What bizarre natural
phenomenon was found here?

And what part did Thomas
Edison play in its discovery?

I never get tired of this.

This is what ignited my love for science.

[narrator] And in the
frozen fjords of Norway,

a top secret cold war submarine base

lies hidden under a mountain.

Why was it built?

And why has it been kept
functional for almost 60 years?

There are some parts
that are still classified.

[narrator] Throughout history,

life underground has
captured our imagination.

It's very frightening but also
very beautiful experience.



[narrator] Now we're taking
you further and deeper...

There's all kinds of wild
theories of what could be below.

[narrator] ...to unearth
the mysteries of these

underground marvels.

[narrator] Situated off
Ireland's Southern coast,

is a strategic military fortress

built to protect against enemy invasion

for over 400 years.

They were trying to defend
the largest empire in the world.

[narrator] Constructed
with the most advanced

military technology of the time.

This would have made
Cork Harbor impenetrable.

No matter where your soldiers are standing,

you are under constant attack.

[narrator] In a strange turn of events,

this powerful stronghold

went from turning people away

to ensuring they never got out.

It's not surprising we've earned
the title, "Ireland's Alcatraz."

[narrator] How did this harbor

play a pivotal role

in the outcome of a major war?

This marked the arrival of the
American Navy as the global force.

[narrator] For the last four centuries,

many of the world's military superpowers

have searched for a
foothold from where they could

launch an attack on the British Isles.

One region that drew a lot of attention

was Cork Harbor.

Located on the South coast of Ireland,

it is the second largest
natural harbor in the world.

Cork Harbor is key to
the Western approaches

to the United Kingdom.

[narrator] The British recognized

that the harbor offered an
exceptional military advantage.

And so in the 16th century,

the government moved
quickly to claim it as their own.

Professor John Borgonovo

has been studying the island's
military history for nearly 20 years.

Since the 1550s,

there were canon replacements here

to defend the mouth of this harbor

to prevent ships from entering.

[narrator] The 18th century saw

an abundance of military
activity in the harbor,

while the revolutionary
war raged on American soil,

US Navy Captain, John Paul Jones,

chose to wage a trans-Atlantic
attack in British waters

which served as a wakeup call.

As a result of that, the Royal Navy

invested in improving the harbor defense.

[narrator] Shortly after the
rebellion of the American colonies,

another threat lurked off Britain's coast

in the form of French revolutionary forces.

At this point, the British
government invested further resources

in the harbor. This time building

almost entirely below ground.

Yet Cork Harbor posed a difficult
problem for the British Navy.

Although it was a
powerful strategic position,

part of the Irish population wasn't happy

about the prominent
British military fortification

in their country.

Throughout the
centuries, Irish nationalists

have sought to secure
independence from Great Britain.

Ireland presented a potential
threat to British security

because a potential landing here
would be supported by local folks

The platform essentially for a
proper invasion of Great Britain.

[narrator] In the late 18th century,

the British admiralty chose

to redouble their efforts in Cork Harbor

against foreign and internal advisories...

building three semi subterranean fortresses

around the narrow straits

forming the only entrance to the harbor.

Spike Island lay at the head

of the triangle,

looking directly out
through the harbor mouth

into the Irish Sea.

[John Crotty] They were trying to
defend the largest empire in the world.

Nothing in the all of
Britain would be under scale

of what we're standing in today.

[narrator] John Crotty has studied
the history of Spike Island extensively.

Charles Vallancey was the designer

of the fortress here on Spike Island.

He saw the importance of using this harbor

to defend the entire British empire.

[narrator] Spike Island
is centrally located

within view of the mouth of the harbor.

Completed in 1802,

its first citadel, Fort Mitchell

was at the cutting edge
of military technology.

It took thousands of men

over 50 years to build this fortress.

And they carved off the top of the island.

They set the fortress down

strategically placed out
of the line of canon fire.

So you couldn't even
see what was hitting you

when you were coming into
the harbor and being attacked.

It's one of the largest forts in the world.

[narrator] The fort's
distinctive shape was strategic.

The points of the star
meant that British troops

had overlapping arks of fire
over all parts of the island,

making the whole area
one effective kill zone.

They started creating this
protruding walls and bastions

If an attacker did manage
to get to the fortress,

there was nowhere safe to hide.

There were sniper
galleries inside those walls.

And no matter where
your soldiers are standing,

you are under constant attack.

[narrator] Two additional forts were built

t o protect against enemy invasion.

Fort Carlisle was built
on the Eastern approach,

while Fort Camden was on the Western side.

Together the three forts housed 61 canons,

aimed at the entrance to Cork Harbor

in the event of an attack.

But all this heavy artillery

required a colossal reserve of gun powder.

So in the early 1800s,

the British excavated
munition stores and tunnels

to house the hazardous loads of
gunpowder underneath Spike Island.

These tunnels were built by
the British in the early 1800s.

They wanted to keep the
gun powder in a safe place.

Where better to do that,

but not by burning it in these
bump proof, canon proof shelters.

[narrator] The problem with gun powder

is that it's uniquely unstable,

no matter where you store it.

[Crotty] It wasn't uncommon
for gun powder to explode.

Not only as a result of an enemy attack,

but it was a very dangerous
substance to begin with.

It was just so volatile

that it would take nothing
more than a candle

to make that gun powder to go sky high.

[narrator] To prevent explosions,

the fort's designers came
up with a clever solution.

They made lighting tunnels all
around the back of these rooms

and they put a pane of glass in between.

So a man would be able to
go around this lighting tunnel

with a live flame lamp.

[narrator] Each chamber
had a lighting window,

allowing the guard to safely shine light

on to the gun powder stores
without risk of explosion.

The paned glass would
allow the light to penetrate,

so there was no danger of
the gun powder being ignited.

They had to dig these tunnels

tens of meters underground

that wrapped all around.

So it was an enormous project.

The largest construction project

in the British Empire at the time.

[narrator] Across the bay,

Fort Camden's 25 heavy cannons

required even more
underground gun powder storage.

[Byrne] This was the main
entrance of the magazine.

[narrator] Jason Byrne has volunteered

at what is now known
as Camden Fort Meagher.

For over a decade.

Soldiers would come in
here in their outdoor uniforms

with hobnail boots and brass
buttons and metal on them

that could create sparks.

They took off their outdoor clothes.

Their magazine clothes
would have been like a pajamas.

Cotton or linen top with wooden tag holes

and white cotton linen
trousers and slippers.

Once they were safe,

they entered down into the magazine.

[narrator] The staircase
leading to the underground space

was carefully engineered

to provide maximum protection

and the fastest possible access

to the hidden gun powder magazines.

[Byrne] Even though
we're 30 feet underground,

the ground was originally dug back

and this was built as a
free-standing structure

and then the earth was
filled back in and around it.

Sort of like a light house or a tower.

Each stone is cantilevered
back into the wall supporting it.

So there is no central support.

In the center originally,

was a timberline shaft.

The barrels were brought in here

and could be winched up to the top,

and then just brought out
to the different gun positions.

It's a very well made structure.

[narrator] Deep beneath the fortress,

there was space for enough gun powder

to keep the guns firing for several days.

This was built

to store 960 barrels of gun powder.

There is nowhere really

that you could have put the magazine

to protect it from enemy
fire except for underground.

And then, they covered
it over with 12 feet of soil.

So we're were very well
protected under here.

That's double walled.

The walls are three feet thick.

It's probably the most
critical part of the fort.

[narrator] While going
underground minimizes the chance

of the gun powder
magazine from getting hit,

subterranean spaces

are plagued with damp conditions

and that presented another major issue.

[Byrne] One of the big things
about keeping gun powder

and especially keeping
gun powder undergrounds,

is that you wanna keep it dry.

Wet gun powder is no good to anybody.

To control that,

there is a fairly elaborate
ventilation system in this building.

If you look along the walls here,

you will see a lot of holes in them.

Hopefully, keeping the gun powder dry.

[narrator] The Cork Harbor forts

were so powerful and the risk to invaders

entering the approach channel so high,

that throughout the Napoleonic Wars,

the guns were never even used.

But by the mid-19th Century,

a new crisis had emerged in Ireland

and this time it wasn't war.

Soon, the fortress that
was originally designed

to protect its residents from danger,

was about to become hell on Earth.

In the mid-19th Century,

Ireland was engulfed in a crisis.

By 1844, the repeated
failure of the potato crops

had driven millions of people
to the brink of starvation.

This disaster along with political tensions

associated with British rule in Ireland,

forced a million people
to flee the country.

During the turmoil,

British rulers offered
little compassion or aid

to those suffering.

Instead, compounding the problem

by enforcing harsh punishments

for the desperate actions of the starving.

Prisons were overrun

and Spike Island located in the
middle of Cork Harbor was converted

to hold the destitute inmates.

[Crotty] The felon pushed the numbers
being arrested to such a high level

for such trivial things as
stealing food to stay alive.

So they converted the
entire fortress into a prison.

It was a bad solution

but it was the only solution
that they had at the time.

There has never been a larger
prison in Britain even before or since.

It's hard to imagine a worse
place for a person to be kept.

It's not surprising at all

that we've earned the
title, "Ireland's Alcatraz."

[narrator] By the late 1850s,

the world had seen
many upgrades in warfare.

With the widespread introduction

of steam propulsion in ships,

and the growth of the French fleet,

a commission proposed
that Britain's coastal defenses

including Cork Harbor needed enhancements.

Fort Camden's massive
overhaul began in 1861

with over half

of its new structures
being built underground.

[Dr. Borgonovo] During the
industrial age, military technology

is evolving rapidly
just as all technology is.

We basically have canons
that are able to shoot

much further and much more powerful shots

and you can also mass
produce artillery shows.

[narrator] In the 1880s and 1890s,

the artillery was upgraded

with breech loading rifle
guns and newer canons.

[Byrne] This is where the
gun would have pointed out.

A ten-inch gun, the barrel fitted

fairly neatly out of this hole.

Most of the harbors are
only 1200 or so yards away.

So any ships coming in,

these guns are firing pretty
much at point blank range.

[narrator] Upgrading the forts
allowed for superior protection

of the artillery battery
from incoming threats.

[Byrne] This is the iron
seal that protected the gun.

It's layers. Iron, bitumen,
iron, bitumen, iron.

It's a sandwich.

It's over two foot thick.

The idea being, if it took
a hit from the outside,

the vibration on the outside is
damped by the bitumen in the middle.

There is 20 feet of concrete above us

and soil covering all of that.

So from the outside,

you can't see any of these positions.

[narrator] In 1891, new
tunnels were dug in Fort Camden

for the installation

of the world's first
practical guided weapon,

the Brannon Torpedo.

The torpedoes were

incredibly advanced for their time.

It would have been slid along here

There is a rail upon the roof

over to the launch rail.

The torpedo could be guided

into the site of the ship.

If it missed, it had the
ability to turn around

and do a 180 and come back in
through the other side of the ship.

[narrator] By the early 20th century,

as the World War was getting underway,

a new military technology surfaced

which posed a tremendous threat

to Cork Harbor's coastal defenses.

It became quite strategically important

during the first World War

and a new threat emerged.

[narrator] The Germans

with a Navy significantly
smaller than that of the UK

began deploying U-boats

to improve their odds at sea.

[Dr. Borgonovo] The German
submarines prowed this entire area.

The numbers of sinking of
the Irish coast was massive.

Hundreds of ships were lost.

[narrator] Once the United
States entered the war in 1917,

they needed a naval base

to protect their ships from the U-boats.

And Cork,

as the strongest position West of Britain

was the perfect spot.

[Dr. Borgonovo] You would have
seen probably about 60 or 70 warships.

Probably about 10,000 to
15,000 American sailors here.

And this was really critical

Critical to winning the
war against submarines.

The American escort vessel were
able to basically beat back the submarine.

And it really marked the arrival of
the American Navy as a global force.

[narrator] By World War II
the advented aerial warfare,

the stone forts were finally
beyond viable upgrade.

Cork Harbor had watched
over the Western approaches

to Ireland and Britain for four centuries.

And today it's remembered as a site that's
helped shape Irish and world history.

Beyond the mountains of rural New Jersey

lies a surprising world, half a mile down.

A spiraling network of tunnels, cliffs

and valuable riches spanning over 35 miles.

Our minerals are so strange and so
uncommon in the rest of the planet.

[narrator] Deep underground, from
the dull grey rock is transformed.

And that just scratches the
surface of this world-famous site.

The miners never realize
these hidden effects were here.

[narrator] What is this
mysterious phenomenon

and why was Thomas Edison
to thank for its discovery?

[Kroth] I never get tired of this.

This is what ignited my love for science.

[narrator] Hidden deep
in the hills of New Jersey

is a mine where 120 years ago

a truly enlightening discovery was made.

Best known for its busy beaches,
busy highways and diverse culture,

the Garden State isn't typically
recognized for its geology.

But nestled in the small town of Augsburg

is the location of the world's
richest zinc ore deposits.

We're on the property
of the Sterling hill mine.

In Sussex County, Northwest New Jersey.

[narrator] Bill Kroth is geo
technical engineer in Sterling Hill

and an expert in the
regions geological history.

There were over 400 iron and copper
mines in the state of New Jersey.

[narrator] Starting in the 1600s,

early Dutch settlers flocked to the
area in search of two valuable resources

Copper was used to
sheet the holes of ships,

and along with iron was everyday
object, tools and weapons.

Several attempts were made to distract
the precious ores, with little success.

However, the Dutch
didn't leave empty-handed.

Their efforts led to the discovery
of an unidentifiable mineral.

So this is a piece of the ore.

This black material and this is what fools
a lot of people is called franklinite.

And when this weathers
out in the atmosphere

and rain hits it, it starts
to get bronzy color,

[narrator] The bronze-looking material
was like nothing anyone seen before.

And some of the rock was even sent to Wales,
in the UK in 1972 for further research.

It wasn't till decades even a century later
that they figured out that it was zinc.

[narrator] By the 19th
and early 20th century,

zinc was in high demand across the globe.

It was used to galvanize other
metals to keep them from rusting.

Its heyday was during the World War II,

when there were ships around
the clock to produce the zinc.

To mix with copper to get brass,
brass is used for making shell casing.

[narrator] But zinc wasn't the only
treasure hidden inside Sterling mine.

Doesn't look like much from the surface

but there over 35 miles
of tunnel in this mine.

It's only half a mile deep, so
we're talking 2,700 feet deep.

[narrator] That's more than twice as
deep as the Empire State building is tall.

Yet the most impressive parts of the
mine are not visible to the naked eye.

So, this looks like regular
rock and this is regular rock.

But we are heading to a very special area

where we actually gonna be in the ore body.

[narrator] This amazing discovery
was almost missed by early miners,

until Thomas Edison became
interested in the industry.

In 1890, Edison invested nearly $2 million

in an operation that
employed over 500 workers.

He introduced new technique in blasting,

conveying, crushing and magnetic separation

and, of course, electricity.

Prior to Edison's involvement in the industry,
miners worked strictly by candle light,

which was not an ideal working
environment to uncover hidden treasure.

Now we're coming in to the region where

our rocks are world famous

where they are really gonna blow
us away. Wait until you see this.

[narrator] Thanks to
Edison and electricity,

the miners got more
than they bargained for.

You'll see why in a second.

Look at these minerals.
Look at this. Amazing.

No other place on the
planet, such beautiful colors.

[narrator] With the help
of the electric lighting

the once unlit rocks and
minerals buried in the ground

turned a vibrant orange, pink and green.

Amazing. The miners never realized
these hidden fluorescent effects were here

until Thomas Edison's light bulb.

[narrator] But the electricity
was still in its infancy

and the miners were very cautious using it.

[Kroth] When you throw
the switch there's an air gap

in between, and it's quite a large air gap.

The ionized layering between and
we get an electrical spark that jumps.

[narrator] The electric
sparks contain a wave length

of ultra violet light that
reacts with the minerals.

[Kroth] You can imagine
like it was back in those days

but it had these beautiful hidden colors.

That were revealed under sparks.

I never get tired of this. This is
what ignited my love for science.

[narrator] The miners discovered the
glow created by the fluorescent rocks,

could make their work
underground a lot easier.

It wasn't long before they used these
magical colors were hidden in the rocks,

to not only locate but identify
various minerals using these light.

[narrator] When the rocks turned green

it meant the miners were
getting closer to the zinc ore.

The green happens to be
the ore of zinc called willemite.

It's the color of money,
so we'll go after it.

[narrator] Yet the spark
that provided the light

didn't last for a longer periods of time.

So the miners took Edison's lead

and came up with a
ingenious solutions of their own.

[narrator] In the late 19th century,

fluorescent mineral deposit were
discovered buried with the Sterling mine.

Apart from its aesthetic value,

the glow could help to locate valuable
zinc ore deposits below the surface.

Miners relied on a short
electrical burst for illumination.

But to maintain a constant energy source,

which would allow them to go further
into the cave for long periods of time,

the technology needed upgrading.

[Kroth] And improved it on
the spot by raising the voltage

and they could carry these around.

[narrator] The device
they created the iron ore

runs between two ion electrodes
that produce continuous current.

It has a transformer and
is controlled by a switch.

That's where we create the iron spark
that will create the ultra violet light.

Check this out.

[narrator] However, utilizing this new
technology came with its own challenges.

[Kroth] You're walking n a mine that's
dark, tripping hazards. Your feet are wet.

Your hands are wet and you are
carrying a machine that's got 75,000 volts.

But to see these colors, to
pin point where the ore was,

was definitely worth the risk.

[narrator] Since they were discovered

the extraordinary fluorescent rocks have
amazed the miners working in the tunnels.

Like former Sterling hill
miner Doug Francisco.

[Doug] Boy, this brings back memories.

Ah, I'm home.

You can take home specimens.

One guy was bringing a large trunk of
ore on the cage to take home with him

and he dropped it and broke a
foot of a guy down below him.

From that moment on,

the mine said you can take home specimens

but they have to be able
to fit in your lunch box.

[narrator] Drilling and blasting
these rocks needs great technical skill

and miners were required
to follow specific procedures.

Although new comers
sometimes learn the hard way.

Couple of weeks after I started,
they put me working with this old timer.

We spent six hours
drilling this pattern out.

At the end of the
shift, we're gonna fire it.

So we go around the
corner and the bends down

and I start the lean down and said, "You
are not gonna," and boom, he set it off.

And literally I was 15 feet
away around the corner

and it knocked me on
my butt, blew my helmet off

and he just laughed and laughed.
Another lesson for the new guy.

[narrator] The miners
at the Sterling hill drilled

and blasted tunnels deep into the mountain

to find the glowing minerals that
indicated precious ores were nearby.

You can almost trace some of these
hole patterns but that's where it ended.

We would call that a boot hole
because it didn't break clean.

This is a trace of the
drill hole for blasting.

There was drilled in there,

so that means this drift in
tunnel was driven in this direction.

Boot hole, boot hole, boot hole.

[narrator] Once the
ore had been blasted off,

the heavy rock needed to be transported

through a maze of tunnels
back up to the surface.

Fastest and most efficient mode
of transport was the train cart.

[Kroth] I can't tell you how many
times I've driven these things.

[narrator] This Sterling hill mine
operated continuously until 1986,

when owners were forced
to close its doors for good,

due to rising production
costs and falling prices of zinc.

Three years later, in 1989,
new owners purchased the land,

determined to bring the mine
back to life in the next generation.

Today it's been transformed
into a place of exploration

and research open to the public.

[narrator] Dr. Earl Verbeek is
resident geologist at Sterling Hill.

His passion is studying these unique rocks

formed over 1.3 billion years
ago by a chain of volcanoes.

In many places, you will find maybe
one to the five fluorescent minerals.

In a very rich place, a very
complicated geology place,

you might find as many
as 20.100 is just outlandish.

[narrator] Thanks to the discovery

and further development of
the fluorescents done here,

it's now a part of our everyday life.

[Kroth] Pretty much any
of the light we use indoors

and that I ight is produced
by the fluorescents these days.

We have a fluorescent stripe in every bill

and the color of that stripe
differs from five to a ten to $20 bill.

Credit cards, driver's licenses and
most of them hidden fluorescent emblems

in them to make them
difficult to counterfeit.

[narrator] Sterling hill mine remains
invaluable to scientific research

and provides the opportunity to deepen
our understanding of the interactions

between the earth and the light.

It also provides a lasting
memory to all who have seen it.

No way could I pick a favorite
out of this pattern of minerals here.

I just couldn't do it.

[narrator] Located within the Arctic circle

is the side of Norway's
best-kept military secret.

A massive underground complex carved into
a mountain hidden below 900 feet of rock.

Equipped with nearly 10,000
feet of deep water docking space,

ammunition depots and barracks,

this submarine base
served as a vital starting point

for Norwegian and NATO
defenses during the cold war.

How does this covert military
facility resemble a villain's layer?

And today how is it been
restored to serve a new purpose

in the event of another global crisis?

There are some parts
that are still classified.

[narrator] In the far North of Europe,

concealed in the rocky
walls of North region fjord

is a military base built to house
the most covert cold war weapon.

[narrator] Norway, a nation
traditionally known for wartime neutrality,

was shaken after its Nazi
occupation during World War II.

And the country wanted to
protect itself from future attack.

In 1949,

Norway was the only member of the NATO

to share a border with the Soviet Union.

There was an uneasy peace
between the two nations.

By the 1960s, the
relationship had deteriorated.

And in 1964,

work on the top-secret nuclear
submarine base Olavsvern began.

[narrator] Geir Bentzen was a commanding
officer at Olavsvern for 15 years.

Location of this top secret naval facility
within reach of the Russian Kola Peninsula

was crucial, because just across the border

was the center of Soviet military activity.

[Bentzen speaking]

[narrator] Situated just over
350 miles by sea from Russia,

Olavsvern offered support to naval operations
in the barren sea and surrounding areas.

[Bentzen speaking]

[narrator] The covert facility was
built in three successive stages

over 30 years,

and cost over 500 million dollars.

For Norway,

building this massive complex
was a huge undertaking.

Yet the country was up for the challenge.

[Bentzen speaking]

[narrator] During the
first phase of construction,

engineers built a
subterranean tunnel system

which served as a weapons storage facility.

[Bentzen speaking]

[narrator] Olavsvern's discreet entrance

was built into the mountain bedrock.

The strong, coarse-grained igneous rock,

known as gabbro,

allowed for tunneling and excavation

with unsupported voids.

[Bentzen speaking]

[narrator] The entire base,

some of which is nearly
900 feet underground,

covers almost 270,000 square-feet

and includes 10,000 feet of
deep water underground docks

that can house and
maintain nuclear submarines.

The 3,000-foot long entrance tunnel

with a large blast door at the front,

leads in and out of these berths.

[Bentzen speaking]

[narrator] During the
second phase of construction,

engineers built a massive
sea water base and dry dock

deep inside the rock.

[Bentzen speaking]

[narrator] Bringing submarines
and small craft into the dry dock

via the main gate, was a complex operation.

[Bentzen speaking]

[narrator] Before the vessels can enter,

the water levels on either
side of the mammoth door,

need to be equal

to reduce the pressure on the structure.

Then we start opening the gate.

Slowly it opens.

You will see straight out to the sea.

[narrator] But once inside,

the base and its facilities
moved like clockwork.

[Bentzen speaking]

Or whatever was needed.

Then the submarine

could go back into
operations the next morning.

[narrator] In 1990,

upgrades were made to the base,

including an enlarged docking berth

that could accommodate
a new submarine class.

The dry dock is about 70 meters long.

To support and dry-dock
Ula-class submarines.

We used to have six submarines

and they could all fit in here.

[narrator] The obscured
entrance to the facility

allowed this new class of subs
to go in and out undetected.

[Bentzen speaking]

[narrator] With temperatures outside

dropping below -30 degrees,

it was imperative that the environment
inside the facility was comfortable.

The concept was for the
technical crew on board

to be able to help themselves
as much as possible.

You can fix electronic
components, for instance,

you can do all that inside.

[narrator] But, deeper inside,

parts of this military
base are highly sensitive.

Even today,

some areas are still off-limits.

Please don't film details.

[narrator] During the Cold War,

Norway's top-secret naval base, Olavsvern,

was a high-security submarine base

for native forces.

And while it provided incoming vessels

with access to maintenance facilities,

inside, parts of the base
were highly classified.

Please don't film
details of the blast doors.

This was top secret,

the capacities and so on
were restricted information

and we still keep it restricted.

[narrator] However, a
few of the weapon depots

are currently accessible.

[Bentzen speaking]

[narrator] The storage units
have been carefully constructed

to safe-guard the fragile torpedoes.

[Bentzen speaking]

[narrator] The torpedoes
need to be stored over water

for safety reasons.

[clicks]

[narrator] In addition to its
massive underground arsenal,

Olavsvern also contained barracks,

offices and workshops.

[Bentzen speaking]

[narrator] By December, 1991,

the Soviet Union collapsed,

marking the end of the Cold War.

In 2009,

Olavsvern was decommissioned
and sold to private investors.

We saw that we could combine

a civilian military operation here

at this base.

[narrator] Geir Mikalsen is
now in charge of the future

of this extraordinary
subterranean facility.

His connections to the base run deep,

as his father and other
members of his family

served at Olavsvern during the Cold War.

[Mikalsen] Our plans going
forward is trying to attract

both military and civilian activity

that could be combined with
military activity at the base.

[narrator] The base is already
a trusted military training facility.

[Mikalsen] We managed to
get the Royal Dutch Marines

to train here for two and a half months.

They came here with amphibious vessels

and trained on landing
operations from the base.

We see an increased military activity,

especially of the allied navy vessels.

Our hope is to attract

these navy vessels to come in here for

logistics stops, fuel stops,

and crew changes
where they could use the...

the mess facilities, the accommodation

for the crew either signing off

or signing on the vessels.

[captivating music playing]

[narrator] Far from being a Cold War relic,

the Olavsvern subterranean military base

is managing to reinvent itself.

But, the balance between
civilian and military use at the base

could change at any time.

There are some parts that we
are not willing to share with you.

It's somewhat still classified.

If we turn this base into a more
permanent military operation,

these facilities may be used again.