Original subtitles

Narrator: A marooned structure in america with an infested past.

In every direction you see nothing but ocean,

this place is truly far out

but the importance of this site cannot be underestimated.

The brutalist palace once home to a Bulgarian dictator.

When it was completed, the ruler of the country

decided he liked it so much,

he was going to keep it all for himself.

An Australian island where criminals created a safe harbour.

This place which was designed to house the worst of the worst,

ended up being a vital part of Australia's response to war.

And the colossal wartime project

the Nazis thought no one knew about.

The British did something very smart,

they let the Germans keep working on it.

Decaying relics...

..Ruins of lost worlds...

..Sites haunted by the past.

Their secrets waiting to be revealed.

Far off the southern tip of Florida usa,

is a ruin lost at sea.

So most people think that key west itself is remote,

but this place, this is even further remote than that.

Though this is technically part of the us,

it feels like you've dropped off a map.

Cast adrift on a small island,

its appearance on the horizon comes as a surprise to most.

This place is really a mystery

because it's this huge pile of brick and mortar masonry

in the middle of the Gulf of Mexico.

When you first see this place as it rises up out of the ocean,

you can't help but feel amazed and in awe but a little spooked.

It's weathered the storms of decades

or perhaps centuries but still standing strong.

Distinctive features betray some of the sites secrets

but others remain hidden.

This place looks like a fort but that's not all it was.

This was not somewhere you wanted to end up.

For some of the people who were sent to this island,

it would become a deadly, deadly place.

This vast abandoned structure emerges from the ocean,

more than 100 miles beyond the Florida peninsula.

Adam Hollywood has been making regular trips out here

for almost 20 years.

And knows the lay of the land better than most.

This is the end of a barrier reef system

that runs all the way from Miami out here to the middle of the Gulf.

It creates the choke point for the entire Gulf of Mexico,

so any large ships,

they would have to sail to the south of us

and then up in to the Gulf of Mexico.

When this place was built, the primary concern was piracy.

The United States was interested in protecting shipping

along the American coast and in the Caribbean,

and so this provided a strategic location

to police these waters.

Piracy may have been the motivation for building here

but pirates weren't the only threat.

Ever since the war of 1812 when the British laid siege

to the city of New Orleans

and threatened to cut off all trade exiting the Mississippi river delta,

the Gulf of Mexico became a strategically vital place

for the new United States of America,

so it would make sense that they would build a fort

in the Gulf of Mexico

to basically assert American power in this region.

This is fort Jefferson,

construction began here in 1846

and initially slaves were forced to carry out

much of the heavy lifting.

But details across the site show that change was on the horizon.

This place is absolutely enormous

but if you look closer,

you can also see some irregularities,

some of the bricks are different colours.

In 1861, the American civil war broke out,

remaining in union hands,

this island became a potentially decisive position

from which to blockade the south.

If they could get the fort completed in time.

First two tiers are made up of a light tan or Sandy colour brick

and all those bricks are coming from pensacola Florida.

But when Florida joined the confederacy,

they stopped sending bricks from Florida,

so then we had to start getting bricks from rural Maine,

so when you look at the third tier of this fort,

you'll see the bricks are much darker redder looking bricks.

And they weren't waiting until the right shade came about,

they were interested in completing this job as quickly as possible.

Following the emancipation proclamation,

the union needed to find a new workforce.

The site's location made a choice of whom to employ easy.

Another thing with this island that was really important

was its isolation and that made it ideal for a prison.

In this case union deserters would be sent down there,

Lincoln would have them form a really crucial body of workers

who would do all sorts of tasks on the island.

Although the fort was still not technically complete,

soon enough was built to make it ready for war.

From this fort here, fort Jefferson as well as fort Zachery Taylor

in key west,

the ships that worked out of these harbours

were able to capture over 300 shiploads of supplies

that were going to the south.

While fort Jefferson left its Mark on the civil war,

one prisoner would leave his own imprint on the forts history.

Samuel mudd was the most famous prisoner

we had here in the dry Tortugas at fort Jefferson,

he was convicted of being a co-conspirator

in the assassination of President Lincoln.

On 14 April 1865, in the final days of the civil war...

..President Abraham Lincoln attended a performance at a theatre

near the white house.

While he's watching the show an assassin enters his box,

shoots him in the head from behind

and then to escape, leaps out of Lincoln's box,

catches his boot in some bunting coming down,

breaks his leg.

Whilst on the run,

the assassin John wilkes booth

stops at the house of dr Samuel mudd who set his leg.

Mudd however fails to alert the authorities.

Two days later, suspicions of mudd's complicity

in the assassination were raised

and it proved enough for a conviction.

Samuel mudd himself, he was sent here to the dry Tortugas

at fort Jefferson to do a lifetime of hard labour.

Mudd quickly learned this would be no easy ride.

Tourists pay good money to come to places like this nowadays

because of the beaches, 'cause of the sea, the sun

but nobody wanted to go to fort Jefferson

during the American civil war,

it was, it was basically a one way ticket to death.

Finding even the basic human necessities was a struggle.

One of the absolute challenges in a site such as this one

would be the matter of freshwater.

Evidence in the cells

show the lengths the inmates would go to for water.

They actually dug trenches out in the cement floor

and then bowls that would help store the water.

And so you can see even today,

we had a little bit of rain last night

and these trenches help fill up these bowls of water.

So these would just help give the prisoners

enough freshwater to survive.

A large desalination system was installed

to provide a steady supply of drinking water.

But storing this water in barrels

would inadvertently have deadly consequences.

Something happens that is going to drastically change things for mudd

in prison,

it's going to completely change the trajectory

of his experience there.

On 18 August 1867, a prisoner became ill

and within a short time over 30 people would fall ill

on one single night.

Fort Jefferson had been hit by an outbreak of yellow fever.

This incredibly violent, horrible disease

that could make people so deathly ill,

it causes a yellowing of the skin, jaundicing,

that's why it's yellow fever.

Before long, the fort's doctor succumbed to the disease,

suddenly responsibility for the sick fell to dr mudd.

It's believed that he utilised the forts design to aid his efforts.

Yellow fever is a viral disease that is spread by mosquitos.

Their collection of water that they had desalinated

had actually been a breeding ground for mosquitos

and so that was really the heart of the problem.

This hallway was actually designed

to help create a breeze to vent out the smoke

and the heat from the cannons that would have been in these rooms.

One of the things that Samuel mudd did realise is that

bringing people up on to the second level of fort

seemed to reduce the number of people that were getting sick

here at the fort.

The fact is mosquitos, they tend to stay low to the ground,

they don't fly into a lot of strong wind.

Alongside this, mudd introduced far stricter hygiene procedures

when dealing with the patients and it worked,

mudd's efforts saved many lives.

From his heroic efforts,

mudd was granted clemency and he was freed,

he went home on an appropriately named ship,

the Liberty.

Once home, mudd resumed his own medical practice

where he worked until his death in 1883.

Fort Jefferson itself was never completed.

And by 1874 in a rapidly changing world,

it was abandoned.

Today the fort and surrounding areas

are under the authority of the national park service.

It's a wildlife refuge that not only enables people

to enjoy the nature

but also to have an appreciation

of an unexpected history in an unexpected place.

In Bulgaria,

a sprawling complex hides in the foothills

of the lyulin mountains.

The area is very famous for mineral Springs

where people would go to recuperate.

It was a place for relaxation for important people,

for people of means.

Traces of luxury litter this place.

The architecture, it's a mixture between stark and ornate,

it's got this kind of grandiosity of the place.

This is strange when you consider the country's past,

in recent years,

it wasn't a place known for its wealth.

This extravagant resort is conspicuous in design.

Yet there are no signs to it and it's buried deep in the woods.

Why build something this showy and then hide it?

Architect iliyan nikolov,

worked on the construction of this building,

he hasn't been back here for 40 years.

Iliyan worked here in 1978, his father, pavel,

designed this place.

The costly finish on its now crumbling facade

suggests that this building was designed to be special.

The story of this dilapidated place

dates back to the aftermath of world war ii.

When Bulgaria fell under the influence

of Stalin's Soviet union.

By 1954,

the communist leader, todor zhivkov had taken charge.

Todor zhivkov was trusted by Stalin

and by subsequent Soviet rulers

because he was a yes man.

Zhivkov's loyalty meant that by the 1970s,

he was still in power

and he gave his approval for construction at this site

in 1973.

It was intended as a holiday spa complex

where hard-working party members could come and recuperate

in the regions healing waters.

It's now known as bankya residence.

Iliyan remembers its grand design.

But construction here was shrouded in secrecy.

The egalitarian communist state of Bulgaria

is hiding away something for the privileged

in a state where nobody was supposed to be privileged.

The work was done in complete secrecy

because the government didn't want anybody to know

about the hypocrisy that coursed through every aspect of it.

After this complex was completed in 1977,

zhivkov liked it so much,

he decided that even Bulgaria's elite would not be given access.

This place was meant to be for the many

but one man decided to keep it for himself.

For decades, zhivkov kept bankya residence

as his unofficial private country house

but his behaviour was earning him many enemies.

When zhivkov himself wasn't a particularly nice character,

he was very quick to eliminate any potential threats.

Everyone in his country hated him,

if they had the chance they'd have got rid of him.

As zhivkov's paranoia grew,

his secret police became increasingly aggressive.

And even those beyond Bulgaria's borders were not safe.

In 1978, Georgie markov a BBC world services correspondent

and a Bulgarian dissident was murdered on Waterloo bridge

by a Bulgarian assassin

using an umbrella with a poisoned tip.

And dilapidated structures at the edge of the compound

show how far zhivkov would go to ensure his safety here.

Zhivkov wanted to beef up the security for himself

and the people around him

and so he set up extra accommodation for his secret police.

Unbeknown, even to the architects,

zhivkov added a secret tunnel that connected the buildings.

However, his real protection was ensured by his Soviet overlords

and his close personal friendship with their leader, leonid brezhnev.

Addicted to tranquilisers and alcohol,

brezhnev had serious health problems,

so in 1979, zhivkov bought him here to the bankya residence.

Zhivkov invited him

to come to this sort of cleansing mountain retreat

and he wanted to kind of curry favour

with his kind of Russian masters.

Inside the retreat, brezhnev wallowed in the luxury.

The expertly designed pool took advantage

of all the regions beauty.

The pool itself

was full of bankya's famed healing mineral water.

But personal tragedy soon left todor zhivkov

more cut off than ever.

With the death of his beloved daughter, lyudmila,

in 1981,

zhivkov withdrew to the secluded bankya residence.

He took up almost permanent residence at the site,

and remove himself away from that tragedy.

And he rules Bulgaria

from his little hideaway out in the hills.

He is seen less and less

and Bulgaria is less and less well ruled.

The next year the death of his ally, leonid brezhnev,

followed by the softening of communism

meant zhivkov's days were numbered.

He was finally ousted in a bloodless coup in 1989.

He was actually kicked out of the residence and

then he was held up for trial for embezzling money.

Zhivkov was convicted,

confined to house arrest and died in 1998.

Meanwhile, the life of his beloved bankya residence

had taken a bizarre turn.

A Japanese billionairess bought it to convert it into a golf club,

she repainted the site pink and lived there herself.

The billionaire died in 1999

and after a brief spell as an upmarket brothel,

the bankya residence was abandoned.

Iliyan's father was never given credit

for his unique architectural work.

And iliyan now hopes to reverse the fortunes

of bankya residence.

In northern Germany, on the banks of the river visa

sits a mammoth building.

It's a vast expanse of cement

that is just plonked down in the countryside.

It doesn't have any indications on the outside

of what its function would be.

There is not really any windows,

there's only a couple of openings in the whole building.

And it's cavernous interior seems carefully engineered

to support the Titanic roof.

The struts and the columns that hold up

this very heavy roof are clearly perfectly designed.

Massively manufactured from concrete and steel,

clearly, it housed something very important.

Out of the gloom, a distinct order emerges.

It's organised in to a series of enormous bays

with big thick concrete walls between them

and as you work your way to the last couple of bays,

you can see that they've got water in them.

So who built these watery tombs

and shrouded them in thick concrete and why did they do it?

Dr Marcus meyer is the scientific director here.

We know from the age and from its overall military look

that it was something built during world war ii.

By 1943, Germany was struggling to maintain its foothold

in world war ii.

The writing was really on the wall for the Nazis at this point,

it was only a matter of time

before their reich collapsed under military pressure,

from the Russians in the east,

the allies in the south and the west.

Germany is being bombed

from the British isles, from Italy

and is being strangled by an economic blockade.

This precision building

hints at how Germany planned to fight back.

The location might be a clue,

it's right next to a major waterway that flows into the north sea.

What do you want to put here that needs access to the ocean?

With the allies dominating the skies,

the Germans needed to regain control of the Atlantic.

The most effective naval weapon

that Germany has is the u-boat, the German submarine.

The German u-boat sunk something like 3,000 allied ships,

they thought if they could build enough u-boats

to go out and sink as much allied shipping as possible,

then maybe they could negotiate some kinds of terms

that would be advantageous to them.

The type 21 u-boat is what they have in mind.

This is going to be a diesel-electric submarine

that can keep Germany in the war.

You can't just build it in a shipyard

because the aerial bombing campaign

which is pulverising all the German manufacturing facilities,

so this place has got to be able to withstand a huge bombing raid.

The result is this,

the German's top-secret u-boat manufacturing facility,

codenamed bunker Valentin,

it's located far from the coast away from the allies prying eyes.

Secrecy was Paramount

and it was no mean feat to keep construction

of this enormous bunker under wraps.

The Nazi's greatest challenge was how to build a bomb-proof roof.

They built large arches to hold up the roof,

those are built on site

but then later lifted in to place with cranes

and then more concrete was poured on top of that.

By the time they were done, the roof was at least 15 feet thick.

But the Nazis knew this wouldn't be thick enough

to stand up to the ally's bombs.

So they ordered some sections to be increased to 23 feet.

This vast piece of engineering came at a tragic human cost.

This building was essentially constructed with slave labour,

it's believed they used 10,000 to 12,000 prisoners

to work on this project.

The conditions were absolutely brutal.

It's not known how many sacrificed their lives

to bring this secret facility to near completion

in less than years.

This was conceived as a really fast-paced

assembly line for submarines.

The different submarine components would arrive by rail

and by barge

and then they'd essentially be bolted together in this facility.

The plan was that at each bay,

more of a submarine would be assembled

then passed along the system of rails.

In total, each submarine was intended

to pass through 12 bays

until finally, it was ready to enter the lock chamber.

By 1945, the submarine assembly line

was on the brink of building it's first state of the art u-boat.

But unbeknown to German intelligence, the British were watching.

The British had no intention of attacking

until the moment was right.

They let the Germans keep working on it,

keep pouring man, and material, and time, and money and effort

into this huge project

and the British knew the minute it was done,

they knew exactly what was going on.

On 27 march 1945,

20 Lancaster bombers of britain's 617 squadron

known as the dambusters,

flew undetected towards bunker Valentin.

Loaded with grand slam and tallboy bombs.

They knew exactly how to target the most vulnerable section

of the bunkers roof.

They penetrate the thinner section, the west end

and then they get into the guts of the thing, blasting it apart.

Their timing was perfect.

The British did something very smart,

they could have bombed this project while it was being constructed

but they didn't.

Though bunker Valentin remains standing,

the damage was done.

Nazi Germany didn't have the time or resources to rebuild

and overnight, their hope of victory was gone.

And this enormous structure

never even began producing submarines.

After the war was over,

bunker Valentin had one more onslaught to face.

In march of 1946, the British and Americans

decide that, "hey, this Valentin submarine bunker,

"it's the, a perfect place to test bunker-buster bombs."

They fly a number of missions

dropping everything in their inventory

and amazingly, this Valentin submarine bunker

withstands even this barrage of aerial bombs.

The colossal bunker has been slowly crumbling ever since.

In Australia, in the middle of Sydney harbour

sits a tiny island.

It's cluttered with rusting cranes,

old industrial-looking warehouses and washed up boats.

An incongruous villa stands alone.

And beyond that sits an imposing structure.

There are these big windows and the airy rooms

but there's something else.

There are bars on the windows, tiny cells inside,

clearly most of the people here were not here by choice.

The building is covered in spikes and hand-carved scratches.

Clues as to who built the industrial structures

that crowd this place.

There's what looks like a huge warehouse

with a turbine inside

and there's a sign on it and it reads, "Scotland."

Below ground, there's more.

An eerie tunnel runs for almost 200 yards

right through the belly of the island.

What was this built for?

Polly nowicki has spent seven years exploring this island,

which was first inhabited

by Australia's indigenous eora people.

They called this place wareamah

and it was a special sacred place for women

to travel in canoes here

and it was a place of childbirth, for privacy.

But when the British arrived in the 18th century,

they changed this place from a cradle of birth

to something far more deadly and they gave it a new name.

The name makes it sounds like quite a chirpy chipper place,

however it was anything but.

Renamed cockatoo island,

it was perfect for what the British had in mind.

Britain and especially London had a crime problem

but they didn't have enough prisons either.

Their solution was clear, Australia, the great southern land.

In 1788, the area that we now know as Sydney

was opened up as a penile colony for the British

but it quickly became overcrowded

and this is where cockatoo island comes into the picture.

The first convicts to arrive here in 1839 faced a brutal task.

The convicts excavated tonnes of rock

to construct their own prison buildings.

Each convict was assigned a signature,

they would use a small chisel to carve out this shape,

you can see the x's,

the lines and the different kind of shapes,

so each signature meant that they were assigned

a different amount of bricks to build.

They built themselves a grisly punishment block.

So this is solitary confinement,

where they would keep prisoners for up to 12 days

with only half a pound of bread.

The abandoned jail reveals the appalling living conditions.

On the windows, you can see that men have actually grabbed up

to try and get a breath of fresh air

and we have a diary entry from reverend John pendrill

and he describes walking up the road here

saying that he could see up to 20 faces

pressed up against the bars,

just trying to get a breathe of fresh air.

Only one prisoner ever managed to escape

with the help of his wife who was over on the mainland.

She rides the horse there,

she climbs down the edge of the cliff

and she swims to cockatoo island,

it's about a 20-minute swim,

there's bull sharks, strong currents,

all sorts of things in her way,

on top of her supposedly being pregnant.

She gave him what he needed to cut his shackles

and he manages to swim to the other side to freedom.

Once the prisons construction was completed,

the inmates were set to task on an even more formidable challenge.

One that would only further the might of their oppressors.

During the 19th century,

European nations became much more interested

in expanding their empires in south east Asia and the pacific.

Britain needed a place in this part of the world

where they could repair and maintain ships.

It was decided that cockatoo island, with its deep-water

and abundant supply of convict labour

would be the ideal location.

They started work on a dockyard in 1847.

This is fitzroy dock,

it was constructed by convict labour.

It was pretty tough work, the stones are quite large

and they had to carve it away with a small kind of pitch hammer.

Their assignment was digging three feet a day

into the bare rock.

An estimated 1.5 million cubic feet of rock was excavated

and it was only supposed to take 470 days

but it ended up taking years due to the unruliness and unrest

of the poorly treated convict workforce.

By 30 September 1857, the dock was finally ready to use.

Without water, it's about 4m deep,

it's not as deep as it looks but it is quite wide and quite long.

But there was a problem,

there was no power on cockatoo island and nowhere to build the generator.

To transform the basic stone dock in to a modern naval powerhouse,

chief engineer, gother kerr mann, was forced to take drastic measures.

Marks on a sandstone cliff face reveal what happened next.

There's these lines of sort of dynamite ridges

where he's dropped that dynamite down

and he blew out that side of the island.

He was changing the shape of the island

to make way for this huge turbine haul.

In one of the biggest structures on cockatoo island,

cutting edge technology gave fitzroy dock the capacity

to build and repair modern warships.

Inside the turbine hall, this is one of our iron giants,

it came from Scotland in parts

and it is actually a huge scale lathe

and it's used for sort of carving out metal.

And to enhance the scope of their prized facility,

the British commissioned another even bigger dock.

Naval technology doesn't stand still

and as sail ships gave way to steamships,

the dock had to be changed

to accommodate these newer larger vessels.

So now, the convicts had to carve out this,

sutherland dock,

it was the biggest single dry dock in the world.

It included five enormous hand-hewn slipways

where ships were launched.

These are two of our slipways on cockatoo island,

this was a very busy place at the height of these launchings,

it was very popular.

The addition of a tunnel to move workers

and machinery underground,

made cockatoo island the leading naval facility

in the south pacific.

This place which was designed to house the worst of the worst

ended up being a vital part of Australia's response to war.

Throughout the first half of the 20th century,

it was put to the test.

After docking nearly 2,000 ships during world war I,

cockatoo island would play a vital role in the next one.

After Japan entered world war ii in 1941,

the stage was set for naval warfare in the pacific.

Submarines came in for repair,

warships docked here, this place was a hive of activity.

And when the American warship USS New Orleans

was bombed by the Japanese in 1942, she retreated to cockatoo island.

Although the dockyards were able to make the ship fighting fit again,

the real damage had been done.

This is where it came, so in 1942,

they would dockside here up to 60 lead-lined coffins

to send back to america.

After the war, shipbuilding and repair declined.

The last ship to be constructed on the island was hmas success,

which launched in 1984,

it was the largest naval vessel ever to be built in Australia.

Finally in 1991,

the cockatoo island dockyards closed down.

Today, this treasure trove of maritime industry

needs preserving.

We're constantly working on trying to rehabilitate

all the old machines on the island,

that's interesting, innovative and fascinating.

And the forced labour of the cockatoo island convicts

will not be forgotten.

Sometimes places created out of unfreedom

serve a vital purpose in protecting freedom and democracy.

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