Original subtitles

In New Jersey, a secretive facility infiltrated by a Soviet spy ring.

It's believed the damage they did to national security was incalculable.

A palatial compound in Peru that held lavish parties for

the country's elite.

But something terrible was happening right underneath their feet.

A subterranean labyrinth in Wales at the heart of

a booming global trade but riddled with danger.

He was working in this area, and unfortunately,

the blast went off early.

And an island stronghold in Greece besieged by the Nazis.

This battle is such a disaster for the allies that it gets called

Churchill's Folly.

In the lowlands of New Jersey, USA, are the remains of

a sprawling complex linked to a devastating infiltration.

We're just a few miles from the Jersey shore in

a typical residential area with wide tree-lined streets.

But this one area is set apart - lots of wide-open spaces,

buildings that look like they were constructed as part of

a unified project.

There appear to be theatres or lecture halls

so was this maybe a school or a university?

But other areas start to paint quite a confusing picture.

One building has a room, it's all filled with inward facing cones.

It feels otherworldly, like something out of a sci-fi movie.

You get the feeling that there was something very advanced

and highly classified happening here.

For decades, this facility was at the cutting edge

of military research, but that would make it a target.

You could argue that this was the worst case of

internal espionage in American history.

Melissa Ziobro became the official historian

for this innovative complex in 2004.

For close to 100 years, this site was essential

to making sure that the US Army was the best prepared

and best equipped in the world.

It was built to solve a fundamental problem that any military faces -

how do you ensure accurate communication

in the midst of battle?

Wars are won and lost over information.

If you can figure out where the enemy's strong,

where it's weak, and then convey that information

to your troops effectively and quickly, you have an edge.

In May 1917, just a month after America joined World War One,

a temporary camp was established here.

It was dedicated to training the Army's signal corps.

This was a group completely devoted to the correct transmission

of information under the harshest conditions.

They used telegraphs, telephones, even carrier pigeons.

In recognition of the crucial role they played in defeating

Germany in 1918, the camp was soon transformed

into a permanent installation.

In the gap between World War One and World War Two,

the world was changing rapidly.

The aircraft carrier, mechanised transport, meant that the wars of

the future were going to take place over even larger expanses

of terrain or ocean.

That would strain the existing communications technology

New, approaches would need to be developed and soldiers would

need to be trained to use all this new technology.

We are in one of the barracks buildings on Barker Circle,

the first permanent construction done here on base.

They were very involved in early wireless technologies, early radio -

they were testing air to ground radio.

The high-tech innovations made here led to this place

developing a nickname - the Army's House of Magic.

But its official name was Fort Monmouth.

During the 1930s, they made a pivotal breakthrough with

a technology that would change warfare - radar.

The radar systems developed here would be deployed on many fronts.

One of the first was Hawaii, the home of the US Pacific fleet.

There are actually radars from Fort Monmouth at Pearl Harbour

on December 7th, 1941.

They detect the incoming Japanese planes.

Panicking at what they saw, they reported the

incoming planes to their superiors.

But the radar operators told them, "Don't worry about it.

"It's probably birds, or maybe it's our own planes."

Because the technology was just so new, people didn't understand it,

they didn't trust it.

And of course, then the Japanese attack happens.

And now back here at Fort Monmouth, the radar folks are

at first horrified - they think that their technology has failed.

Then they find out, no, it worked but the warning wasn't headed.

This will go down in history as one of the great

communications disasters in modern warfare.

Japan's raid on Pearl Harbour turned out to be

a spectacular success for them, sunk much of the American fleet

in the harbour, killed 2,400 American servicemen.

It was an epic disaster for the US.

Thrust into global war, Fort Monmouth's mission

was now more critical than ever.

Thousands of civilian engineers were bought into the signal corps

to create vital new communication technologies.

This would have been a highly classified facility.

The anechoic chamber absorbed sound and electromagnetic rays

and allowed personnel to test things like antennas and radars.

As well as further advances in radar, they also developed

groundbreaking backpack radios.

These made a vital difference on the battlefield.

The technologies coming out of Fort Monmouth were

the envy of the world, and so there was

a constant recognition that we might be infiltrated.

Yet Fort Monmouth had already been compromised with

a mole embedded within its ranks.

Julius Rosenberg joined the Army Signal Corps

Engineering Laboratories in 1940.

He worked as an engineer and inspector for them until 1945,

but early in the war he had been recruited as a Soviet spy.

The history here is tricky.

The Soviets were nominally America's allies in fighting

the Germans, but everyone knew the Soviets would again be

America's enemies at some point after the end of the war.

Julius Rosenberg was perfectly positioned

to gather as much information as possible.

And he wasn't operating alone.

Rosenberg and his handlers recruited two more people

who worked at Fort Monmouth - Joel Barr and Alfred Sarant.

Rosenberg's spy ring copied more than 9,000 pages

of top secret documents, information about 100 different weapon systems.

In one case, Rosenberg obtained the actual unit of a proximity fuse,

an incredibly vital piece of technology.

He literally put it in a box and wrapped it up as

a Christmas present for his Soviet handler.

As World War Two was morphing into the Cold War,

Rosenberg continued to smuggle top secret material back

to his Soviet overlords, now America's primary foe.

In this dawning nuclear age, the stakes were higher than ever.

He recruited his brother-in-law who worked at the post-war period's

most important, most top secret project, Los Alamos,

where they were doing the work to develop the atomic weapon.

The information that Rosenberg passed on to the Soviets

allowed them to greatly accelerate their own programme

to develop an atomic bomb.

On the 29th of August, 1949, the Soviet Union tested

their first nuclear weapon.

It was almost a carbon copy of the Fat Man Bomb

developed at Los Alamos.

US intelligence investigated a potential leak

which eventually led them back to Rosenberg

and his co-conspirators who began their betrayal at Fort Monmouth.

Helped by a tip-off from the Russian handlers,

Barr and Sarant fled to the Soviet Union where they spent

the rest of their working lives developing new weapons systems

for the Communist regime.

Julius and Ethel Rosenberg were not so lucky.

Ethel's brother, David Greenglass, implicated the pair

after his own arrest in June 1950 for leaking confidential information

from Los Alamos.

The Rosenbergs were put on trial in one of the most publicised

and closely watched events in American history.

They were both sentenced to death and executed at Sing Sing Prison.

Two months later, in 1953, the Rosenbergs' connection

to Fort Monmouth was pounced on by a fanatical anti-Communist crusader,

Joseph McCarthy.

A flamboyant senator Joseph McCarthy was taking advantage of

the concerns about communist infiltration to boost

his own profile and career.

McCarthy claimed that Communists had infiltrated all sorts of branches of

the US Government, from the State Department to the military.

So once McCarthy knows that Rosenberg had worked for

the signal corps - Fort Monmouth is the home of the signal corps -

he becomes convinced that surely there must still be a

communist spy ring operating.

He actually visited the base as part of his investigation

in the fall of 1953.

He made a big show of how he was here and he was, you know,

personally trying to root out these Communists.

MCCARTHY:A complete, wholehearted support now of the commanding

generals in Fort Monmouth who want to clean Communists

and potential espionage agents out of their organisation.

He went on to hold a series of hearings into

the "subversive activity" he believed was still going on here.

His allegations were reckless, they were flamboyant,

they weren't really based on any inside information on his part,

but any time McCarthy talked, he could be guaranteed

a bank of TV cameras.

Workers were suspended for anything from attending

a benefit rally for Russian children, to having a name

similar to someone else who was a suspect.

Based on McCarthy's allegations, the officials at Fort Monmouth

suspended 42 employees.

Of the 42 accused, all but two were reinstated by 1958.

But 15 years later in 1973, after a military reorganisation,

the signal corps was relocated.

What remains behind here at Fort Monmouth is something known as

the electronics command, and then we start getting into

things like night vision technologies and GPS

and early cell phones and on and on and on,

up through the global War On Terror.

The base was officially closed on September 15th, 2011

and with that, nearly a century of US Army occupation

came to an end.

But Fort Monmouth would have one more brush with fame.

Bruce Springsteen, who is a Monmouth County native,

practised here in the Expo Theatre that we're standing in.

I have met Bruce. He is lovely, you know,

he's just another Jersey Shore guy who happens to be

an international rock star.

Today, like many retired US Military bases, there are plans

for Fort Monmouth to be converted to various kinds

of civilian uses including business and housing.

And there are plans under way to turn parts of the campus

into a movie studio.

In North Wales, near the Irish Sea,

is a scarred landscape that helped inspire Tolkien's Mordor

and Middle Earth.

We're in the ancient rugged mountains of Wales,

it's one of the wettest parts of Britain,

cloudy and misty,

but the landscape has a special majesty.

But the landscape around here isn't pristine,

it's deeply scarred and there are huge piles of rubble

and debris everywhere.

You see old structures,

some of them in ruins,

with all kinds of equipment laying around,

clearly there's something in

the hills here that was worth an enormous amount of human effort.

This material was carved out of the land,

transforming the region

and creating a vast unseen labyrinth.

When you descend into the mountainside,

you enter a completely different world,

it seems like there are miles and miles of tunnels

and then interspersed along them these enormous cavernous rooms.

But the material they were mining was prized across

the world, from New York

to San Francisco, even as far as Australia.

At one time,

half the buildings in New York were covered with this material.

Phil Lee Jones has a deep connection to this site.

He gives tours around

the complex, where his forefathers once toiled.

I can go back about five generations

of my family working in these places,

probably more. You can imagine all the machinery,

all the wheels turning, it'd be a very noisy place,

it would be a very busy place.

As far back as Roman times, humans have tried to extract

a precious resource from this land.

But in to the mid-1800s that extraction began

to change it beyond all recognition.

From rolling green hills into

the blackened landscape visible today.

This whole enormous complex began

with one man's determination

to find his fortune in these barren hills.

Entrepreneur John Greaves arrived here in the 1840s.

Greaves was convinced there was

a seam of what was known as blue grey gold somewhere here.

He just had to find it.

That blue grey gold was a precious rock called slate.

Slate had been mined in these hills for many years

and there were little quarries all over the place,

but the really good slate was found deep within the hills.

He dug for three years and found nothing,

the story goes that he sank his entire fortune into

the search and was on the verge of bankruptcy.

But it says something about what kind of leader he was

because his men were willing for a time to work for free,

they also believed that he was on the verge of a great discovery.

Then, in 1849, his prayers were answered.

They found what's known as the Meirionnydd Old Vein

and they began to follow it deep underground.

Eventually, they would dig out 250 chambers across 16 levels,

stretching 1,200 feet from top to bottom,

and it's all connected by 25 miles of tunnels.

This is Llechwedd Mine

in an area called Blaenau Ffestiniog, which became known as

the slate capital of the world.

The slate from Wales has a reputation to being some of

the best in the world. It's very smooth,

has a beautiful colour, it weathers well,

and despite being easy

to split on one axis it remains extremely durable,

that makes it a wonderful building material.

Highly resistant to fire and corrosion,

it's also waterproof, lending itself perfectly to roofing.

Slate roofs can last 100 years, even a couple of centuries.

Wagons would be coming in with big slabs along

the rail tracks here from underground.

They'd come to these sawing tables

and then they were sawn into manageable blocks

and then they were transported down

to these cubicles down over here where then they would be turned

into finished roofing slates.

Into the 1850s, it was being exported to all corners of

the globe, giving rise to the saying Wales roofed the world.

It was a fact not lost on the mine's owner.

Greaves was an astute businessman

and he invested in a series of railways

and shipping wharfs to ensure that he could export his slate around

the rest of the country and the world.

As San Francisco was having a huge building boom due to

the gold rush, a lot of the buildings were roofed

with slate from this mine.

Greaves' operations were proving to be a huge success.

But even by the standards of underground mining,

slate mines were particularly hazardous.

It's hard to imagine just how dangerous

and difficult this work was.

First of all, no electric lights,

so they're descending deep, deep, deep into

the mountainside with a candle at best.

They can see basically what's in front of their faces.

The miners could be crushed to death by cave ins,

burnt by gas explosions or blown up by gun powder.

This is what happened to my grandfather,

he was working in this area,

and unfortunately the blast went off early

and he lost the use of his hand. His hand was mangled,

it was like that, couldn't straighten his fingers out,

he had a big scar on the inside of his wrist

and glue freckles all over his hand,

it's where the slate had gone in, underneath the skin,

so I can appreciate the dangers.

But there was another unseen threat, perhaps the biggest of all.

Mining and processing the slate was very dusty

and the workers had no protection against it,

they spent their lives breathing in harmful silica dust.

The Government was so concerned they did an enquiry in

to the death rate in these mines

and they found that it was even worse than that of coal miners.

The risks would eventually provoke the miners into action.

In 1874 a mine workers union was formed.

This is one of the first places where there was

a real effort to unionise the work force,

to fight for some of their rights,

to fight for greater safety, better pay.

At this movement was gathering pace,

Llechwedd went through a period of transition.

John Greaves died in 1880

and passed the operation over

to his son, also called John Greaves.

He was soon faced with

a wave of strikes that swept across the region.

And a recession which dragged on into the 1890s

and was compounded by a changing global market.

There was increasing competition from cheaper slate bought in from

abroad including mines in Pennsylvania, which were originally set up by Welsh miners.

So soon, the miners in Wales were competing against some

of their former countrymen.

The industry's decline continued into

the 20th century, exacerbated by the great depression

and two world wars. It would never fully recover.

Underground mining eventually ended here in the 1980s.

That's the downfall of Welsh slate, it's the best in

the world but it's the most expensive in the world as well.

The slate landscape of North West Wales is now

a UNESCO World Heritage Site.

But Llechwedd has been repurposed to boost employment.

In 1972, the Llechwedd Slate Caverns opened to

the public as a tourist attraction.

As well as historical tours,

a company called Zip World has turned several former slate mines in

the area into adventure playgrounds, which include

the fastest zip line in the world.

In Greece is the rugged island of Leros,

a strategic outpost that's been the envy of leaders

and dictators through the ages.

On one of the largest peaks is

a strange three-sided formation made of concrete.

From the ground, this just looks like some concrete construction,

but when you get above ground

and you look down at this place,

that is one strange three-sided structure down there.

Though unique looking,

it becomes clear that it doesn't stand alone.

It's part of a wider network.

Low concrete buildings, tunnels, bunkers,

towers with high vantage points,

these must be some type of military structures,

but they've fallen into disrepair.

Is this natural decay or signs of a more violent event?

Up close, the walls riddled with bullet holes

and pock marks provide the answer.

The people on this island suffered a lot,

they were the victims of other people's war.

On the Greek island of Leros,

shattered structures are all that remain of

a bitter conflict that ripped this quiet community apart.

This modern sculpture was the acoustic mirror.

It was a concave structure that,

trapped and amplified the sound of the incoming aircraft.

Local resident Nicos Phocas has been entranced by these formations

for decades.So the operator would work within this trench.

When he heard a noise, let's say now here,

he knew that it was coming from that direction.

Around it, there was a lot of anti-aircraft guns

and also the command centre for all the air defence control.

Leros is part of Greece today,

but these structures date back to an era when

the island was under foreign control.

This aircraft warning system was part of

an extensive network of fortifications,

built in the 1920s and '30s,

on the orders of Italian fascist dictator Benito Mussolini.

Their purpose was to protect

the island's greatest strategic asset,

a port that would allow Mussolini to challenge

the British Navy's domination of the region's seas.

This island is providing a massive naval base,

a deep water port that enables the Italians

to keep sea power active against

rival powers in the Eastern Mediterranean.

It was one of the largest,

naval bases they had outside of, the mainland Italy.

They had seaplanes, they had warships,

they had the submarine base,

it gave them total control of the area.

Mussolini's rapidly expanding navy could now vie

for supremacy in the Eastern Mediterranean...

..able to refuel and resupply in safety under the protection of

the island's fortifications.

It wasn't until World War Two that these defences would be put to use.

By 1943, the region was largely occupied by

the axis powers of Nazi Germany and fascist Italy.

But when the allied invasion

of mainland Italy began in September,

Mussolini's regime crumbled and his armies surrendered.

The race was now on for control of Leros.

The Germans rushed to seize all the areas held by

the Italians who were now seen as traitors.

This made British Prime Minister

Winston Churchill incredibly nervous.

He like Mussolini,

saw these islands as strategically crucial.

And he says we have got to take these islands.

But his American allies would have none of it.

The American decision makers,

Dwight Eisenhower in particular, want nothing whatsoever

to do with trying to grab Italian held Greek islands off

the coast of Turkey.

From an American point of view if we're going to attack

anything in the Mediterranean it's Italy.

But Churchill was hell bent on

seeing his plan through, even if it meant the British going alone.

Churchill rushed 3,000 British troops to the island

to reinforce the 8,000-man Italian garrison now stranded on Leros.

They won the race against the Nazi's, but a reckoning was coming.

On September 26th, the German air attack began.

The Luftwaffe began

a relentless campaign that lasted over 50 days.

Nickolas Daloglou was just

nine years old when the bombardments began.

But the Germans didn't just target military positions,

they attacked the island's towns and villages.

Sometimes, 40 bombers came with each wave

and there were up to six waves per day.

After seven weeks of relentless attack,

in the early hours of November 12th

a German invasion force approached Leros.

Nearly 3,000 elite troops launched an assault across the island,

hoping to claim the vital port for Nazi Germany.

Some units landed right beneath this arsenal of weapons.

These were the mounting bolts for the guns.

The guns placed here were anti-ship guns.

Everyone knows that a naval ship can never win in

a gun fight against a shore battery.

But the cannon on top of this steep peak had a fatal flaw.

The gun is built to fire at something far,

if you bring something up close you can't depress

the barrel far enough to shoot at it.

This gun is fearsome at range, it is useless up close.

German landing craft managed to sneak in under

the blind spot of the guns, they started climbing up the hill.

The Allied artillery troops stationed in this battery were about

to be confronted with hand to hand combat against elite Nazi infantry.

So the German troopers that landed

there were specially trained to climb the rocks.

The fighting was close quarters, hand to hand fight with hand guns.

It was actually like being on a street fight, it was that close.

Once they secured positions on

the rocky slopes, it was impossible to dislodge the German soldiers.

Soon the Allied troops were hemmed in on all sides.

There were also some paratroopers that fell on

the other side of the hill

and there were heavy losses on both sides.

It took the Germans two days to conquer this gunpoint.

With total control of the skies,

the Nazis dropped waves of paratroopers on to

the narrow neck at the centre of the island,

splitting the Allied forces in two.

After four days of bitter fighting,

the Germans had the Allied HQ surrounded.

At that point the British commander surrendered,

he was keen to avoid a massacre.

Out of the 3,000 British troops on the island,

almost 600 were killed

and the rest were either injured or taken as prisoners of war.

The Italians lost nearly 300 men

and in total 8,500 Allied troops were taken captive.

This is said to be one

of Germany's last victories in World War Two.

It's such a disaster for

the British that it gets called Churchill's Folly.

Despite its obvious flaws from the very start,

Winston Churchill remained defiant.

Privately he blamed the Americans,

with their help it might have been avoided.

Germany occupied Leros until the end of the war,

after their defeat it returned to British control.

The island finally became part of Greece in 1948.

Since then the gun battery ruins have sat abandoned,

slowly crumbling down the mountain side.

In recent years, the Greek cultural ministry declared

Leros' World War Two remains as an historic monument.

Leros stands as a living museum of one of the most epic

and tragic battles of World War Two.

80 miles south of Peru's capital city Lima,

is a palatial compound designed by an owner living a double life.

We can see farmland stretching out into the distance,

but surrounded by modern structures is

a building that looks really out of place.

This building has a real mish-mash of features

with its ornate arches and tiling.

There are also gothic spires, castle-like walls and these towers.

The gardens indicate wealth

and opulence which is mirrored inside.

Decorative wallpaper, wood carvings and stained glass windows.

Whoever built this had some serious cash to play with.

On a lower level, we find a trapdoor that leads to

a dark dungeon-like space.

It's a completely lightless network of narrow tunnels.

They could have been for access or storage,

but you can't help wondering if they had a more sinister purpose.

In the early 1800s, a vast estate growing sugar cane

and cotton was acquired by

an iconic figure in Peru's history, Hipolito Unanue.

He was an academic

and politician that supported Peru's fight for independence.

After liberation from Spain was achieved in 1824,

Unanue served as president of the congress

and the minister of finance in the new republic of Peru.

He died in 1833 and the estate passed to his son,

Jose Unanue Dela Coba.

Jose Unanue was determined to build himself

the most luxurious home on the Peruvian coast,

as well as have it serve as a tribute

to his father.

Construction began on this project in 1843.

Local historian David Pino has spent years investigating this place

and has unearthed some surprises along the way.

Legend has it that Unanue bought a Bavarian castle,

stripped it of its doors,

windows and furniture,

and transported them all the way here to decorate his own palace.

He was heavily influenced by North African Moorish architecture

and you can definitely see those influences.

Its construction was a passion project

and continued to evolve for decades.

The many visitors who enjoyed these spaces, knew it as Hacienda Unanue.

The mansion hosted an array of people from

the Peruvian elite and regularly hosted lavish banquets.

But just feet away from these extravagant parties lay

the dark secret behind Unanue's wealth.

The estate was run on a system of slavery.

Unanue didn't just own enslaved people,

his mansion also served as a market place.

The slave trade in Peru had technically been abolished in 1821,

but illicit imports of enslaved Africans into Peru continued, albeit in secret.

It's believed the tunnels were used both to hold

and punish the 400 enslaved people

that Unanue is thought to have owned.

This continued on the estate until 1854 when slavery was abolished by

President Ramon Castilla who became known as the Liberator.

In the 20 years after emancipation,

some 100,000 Chinese immigrants came to Peru.

They were promised

a better life, or coerced into leaving China by recruiters

and bought here to work as indentured servants.

This system of forced labour was brutal

and it led to about half of these Chinese workers dying before

the age of 40 for things like exhaustion,

ill treatment, but even suicide.

But soon these workers would be presented with

an opportunity to seize freedom and enact a measure of revenge.

In 1879, war broke out with Chile.

The following year an invasion force landed 40 miles south of Unanue.

The Chilean Army rampaged through

the area moving north towards

the capital, passing through Canete Valley.

Many of these Chinese labourers joined

the Chileans in ransacking these Peruvian estates.

But their collaboration led to terrible reprisals from

the local Peruvian peasants.

In 1881, tensions boiled over and a riot broke out.

In the ensuing violence and chaos,

1,000 Chinese workers were massacred,

including on the Unanue estate.

Peace only returned to the region in 1884 when

the Chilean Army withdrew. The following year,

Jose Unanue died childless

and the estate passed through his nephew's family for generations.

It continued operating

with its traditional semi-feudal system that exploited

poorly paid workers.

But the 1960s would see seismic changes that would transform Peru.

Revolution gripped Peru

and this place was right in the firing line.

In 1968, Army General Juan Velasco Alvarado led a coup

to seize control of the government

and forcibly implemented agrarian reform across Peru.

The estates were transformed into farming cooperatives,

partly owned by the peasants who worked them.

Jose Unanue's descendants were forced to leave

and the surrounding estate divided up among the poor.

The palace itself was left abandoned and its fittings

and furniture looted.

In 1972, Unanue Palace was declared a national historic monument.

Despite it being open to

the public, this abandoned building has suffered from lack of investment

and has fallen into ruin.

Subtitles by Red Bee Media