Original subtitles

(Dramatic music)

Tom ward (narrates): A sprawling European forest

that hides a destructive force.

This is clearly part of something very, very big

and very, very dangerous...

In the pacific northwest pioneers and pilgrims

at the forefront of an industrial revolution.

Less than a year

after this incredible technological breakthrough, disaster struck.

..A South African ghost town that was gripped by fever...

Something went wrong and really rather fast.

..And odd structures resting in the English countryside.

There's a link between them.

But what is that link?

(Theme music)

Decaying relics and ruins of lost worlds,

forged through years of toil they're now haunted by the past.

Their extraordinary secrets are waiting to be revealed.

(Theme music)

(Rumbling)

In a remote corner of northwest Poland,

just 100 miles away from the German border,

dense woodland conceals a complex of ominous looking structures.

Here we are in Europe in the middle of rural Poland

surrounded by these beautiful pine trees.

Suddenly, tucked away something catches your eye.

Man's been here before

and actually he's made quite an effort

to disguise what he's done.

You're not just in a wood.

You're inside a very old

and very well protected facility that's all around you.

In a way it sort of feels like you've stumbled

on some kind of dystopian hobbit town.

You've got all these doorways covered with soil

leading to something that's hidden in the ground.

Whatever its origins, this place has been removed

from local maps of the area.

The question is why?

Somebody built something very, very strong

and then put a lot of earth over it to protect it

from something very, very dangerous.

You also have some kind of ventilation system

'cause you can see these grates for air intakes or exhaust.

So, who built this strange place?

And what is concealed inside?

(Suspenseful music)

From its very earliest days this eerie underground site

has been surrounded by mystery.

Polish archaeologist grzegorz kiarszys

has spent years trying to unravel its secrets.

The site was known at least from the beginning of 1990s

to Polish citizens but also to some historians

which started to be interested at this place.

But nobody before me did here any archaeological survey.

Recent declassified documents reveal the construction here

began in 1966,

a time when east and west were locked

in a tense military standoff.

There was the constant threat of all out war.

The Soviet union was intensely paranoid

throughout the cold war and they were very worried

about some kind of an attack from Europe.

To counter the perceived threat, the Soviets maintained a presence

in all of their puppet communists states.

Polish army was obliged to build those facilities

based on the plans that were supplied by Soviet union.

Polish soldiers did not have a clue what they were building.

In fact they were told that

they are building communication centre

for Soviet troops.

The idea that the Soviets would have a communications

based in Poland is very straightforward.

It's a great cover.

And due to security reasons, every separate construction group

had access only to a small part of the facility

so, they could not gain an idea of the whole compound.

This is the podborsko cold war bunker

part of a vast network of secret underground military installations.

If it had ever been called into action

it would have posed a grave danger to all of mankind.

The code name of the site was 2001

and we are standing just beside the monolith bunker.

Those doors had to be kept closed

because of that very specific environment

that had to be created inside the bunker.

When you see the size of the door

you imagine the space inside must be pretty large.

It's only by venturing deeper

that the true nature of the complex is finally revealed.

Looking at the bits left behind and that's all we've got to go on,

clearly there was something

very, very sensitive being stored here.

There's barriers.

There's atmospherically sealed areas so that nothing can get in

but more importantly nothing can get out.

And this leads you to believe that there was radioactive material here.

So, I assess it is likely that these facilities were built

to store rn24 or rn28

tactical nuclear weapons ready to be dropped

from Soviet fighter bombers onto NATO forces fighting in Europe.

During the late 1960s

the ussr realised that if it was attacked

it wouldn't be able to get its nuclear arsenal

to Poland quickly enough.

So, it hatched a plan to house atomic warheads

at locations throughout its satellite states.

(Tense music)

They didn't want the allies to know where it was

or even the Polish people to know where it was, it might leak out.

So, they built these carefully hidden, highly secretive

underground bunkers.

At sites like this 500 kiloton warheads were stored,

that were 30 times more powerful than the bombs

that destroyed Hiroshima and Nagasaki.

The Soviets didn't say that they had nuclear weapons in Poland.

They told the outside world that they didn't.

The Soviets gave a false answer for operational reasons.

For more than two decades,

the Polish people were kept in the dark

about what was being stockpiled on their soil.

Clues inside tell us that deadly weapons here

had the potential to blow at any moment.

We are standing now at the main manoeuvring hall

which was used for moving of the warheads.

On the right side we have rooms that were used for the storage

of nuclear warheads.

The equipment here, the pressure gauges

and the sensors are all signs

that specific environmental conditions

had to be maintained.

Military grade plutonium is very prone to corrosion

so, all of the moisture from the air had to be removed

and therefore we'll have dehumidifiers

and a hygrometer which measured the humidity of the air.

State-of-the-art nuclear weapons are sensitive things

and when things go wrong they go catastrophically wrong.

So, temperature control, humidity control,

very, very important, particularly if you're trying to remain secret.

However, it seems that by trying to cover their tracks,

the red army made a fatal error.

At the end of 1969, those bases were finished

and handed over to Soviet troops.

Soviet troops started to work on the camouflage of the site.

But they made a few mistakes.

So, the Soviets start to plant spruce trees

around their installation.

But in Poland the local forest is birch.

And in the Autumn, the leaves fall off.

All you're left with is these thin white stems

and yellow leaves on the ground.

During the cold war

the Americans kept a very close watch on Soviets

using satellite photography.

So, they're looking for human activity.

American satellites could see right past those spruce trees

and they knew there was something going on.

CIA reports now reveal that the us intelligence agency

identified 23 similar installations

spread right across the eastern bloc.

Even with this intelligence, Western Europe was still powerless

to prevent the Soviet warheads being fired.

If a full scale war had broken out,

total annihilation would have been inevitable.

If the war happened, trucks from this base

would be loaded with warheads and then they would move

to those shelters and wait for the further orders.

For more than two decades after the bunkers were built,

the world lived with the threat of a nuclear war hanging over it.

It was only after the Soviet union began to crumble in the late 1980s

that mankind was able to breathe a little easier.

In 1991 Soviet troops were withdrawn from this facility

and it was officially handed over to the Polish Navy.

And with the red army at last gone,

the truth about the abandoned bunkers was finally revealed.

After the cold war there was a treaty

which required the Soviets to open

some of their facilities for inspection.

As part of that process they had to admit

that some of their facilities in Poland

had nuclear weapons in them.

Following the departure of the Soviet army

similar bunkers in the Polish countryside were vandalised

and one was actually converted into a prison.

But this site is preserved as a chilling reminder

of how close the world once came to nuclear destruction.

To be able to see all those structures,

to walk through the corridors of this bunker

is like to have this power to travel back in time.

Every time I pass the doors of this building,

I have this feeling like the Russian troops

have withdrawn just yesterday.

In the heart of america's pacific northwest,

15 miles south of Portland, Oregon,

there's a curious set of structures by a large river.

Look around at this site

and you see industrial spheres, chimneys.

Clearly there was a lot going on here.

What this looks like is an empty shell

of an industrial site.

There are windows broken.

There's rain pouring through the roof.

It's a ghost site.

The many abandoned buildings from different ages reveal that

this place has grown and transformed over time.

At the centre are older ruins that don't seem to fit

with the rest of the site.

Clearly, this has been used for centuries

but for a variety of different purposes.

You get the sense that at one point

this was just teeming with activity from machines and activation

and people and hustle and bustle.

So, how are those structures connected?

And why did the site change so much through the years?

The proximity of the water is clearly

a very important part of this site's history.

And some of the buildings now look as if they've even been destroyed

by the power of that very same water.

Whatever went on here the river is clearly the key.

(Intense music)

This was once the beating heart

of oregano city's industrial district.

Over its 150-year history,

this place has had many different identities.

It has evolved as the needs of industry changed.

But during that time there's been one constant spectacular feature.

So, what we're looking at is the second largest waterfall

by volume in the United States.

There is an enormous amount of potential power here.

So, how would this extraordinary place

manage to harness the raw power of the mighty river?

In clackamas county, Oregon,

a curious set of structures dominates the area.

But most of the remains here provide perfect clues

about the most recent use of the site.

It was for the production of an item with which we're all very familiar.

In more modern times with the demand for paper

and given all the trees in the surrounding area,

this became one of the heartlands for newspaper production.

In its final guise, this was a giant paper mill,

supplying newsprint all across the west coast including

to the 'Los Angeles times'.

Local expert Don Scott has long been fascinated by its history.

So, we're now inside paper machine number four.

This is where the actual paper making took place.

This building would have been filled with people buzzing with activity.

The mill ran 24 hours a day.

It's known as a paper mill towards the latter end of its life

but decades before that it had so many other different uses.

Hidden amongst the modern rusting ruins

are things that are not from its recent past.

These stone blocks form the foundation walls

so what you see is very little of what was originally here.

It's got a long history dating all the way back to 1832.

The first people drawn to the water's formidable

natural strength roamed these rugged lands for millennia.

The native Americans realised the benefits of the area

because of the falls.

With the sheer drop at the end of them,

fish stayed in one small reservoir

making it effectively a natural pantry.

So, for many generations, the native American peoples

were in Harmony with nature, taking fish from the river.

And then when the white Europeans arrived, things started to change.

As the last stop along the Oregon trail

pioneers flocked to the region during the mid-19th century.

What drew them here

was the establishment of a settlement by a man

who became known as the father of Oregon.

When John mcloughlin arrived

he saw an entirely different opportunity in this area

with the force of the waterfall.

And this realisation was the true start

of industrialisation in this area, which expanded rapidly outwards.

So, the most impressive thing about willamette falls

is the sheer power of the water coming over the falls.

You can actually feel the roar as you're standing here.

And you, as you're just completely covered

with the spray

it is... it is truly an impressive sight.

This is the location of the willamette falls saw mill.

The very first commercial site to harness the power of water

and the reason Oregon city

and this vast industrial district exist today.

Before long, flour and woollen mills sprang up

along the river bank and the whole area

quickly became a thriving manufacturing centre.

So, this is clearly a site that's built up over time

and eventually it's gonna become quite

a sprawling edifice but it all started

on the west bank of the river

and then eventually will incorporate the other bank.

But it was another structure, one yet to be built

that would make an even bigger contribution

to Oregon's history.

By the end of the 19th century the site had been used

for all sorts of industrial applications

but it was on the cusp of being used for something even more radical

that would affect not only the area but the wider United States.

It's the crumbling concrete blocks

and rusting pipes near the original saw mill

that hint at the pioneering achievements here.

A power plant was built to harness the flow of water

and it was used to spin turbines.

So, this is the location of the original station a.

What we're seeing here is the outflow of the water

which would have passed by the dynamos

which were used to generate the electricity.

Using water to produce electrical energy was nothing new.

So, what was so special about the power produced here?

And how would it change america forever?

The power potential here is obviously immense.

You're talking about hundreds of tonnes of water

flowing over the falls every minute.

And imagine someone coming 100 years ago

and wanting to harness that power

but knowing the danger, how are they gonna do it?

In 1889 hydroelectric energy

had already been in use for seven years

but transferring it over long distances

hadn't yet been possible.

At this time much of america

was still lit by candles and gas light.

And if that could be achieved it would be a game changer.

Copper lines were strung from the power plant about 14 miles

to downtown Portland.

When the switch was thrown history was made,

the first long distance power transmission

in the United States.

What they did was groundbreaking.

This completely transformed Portland.

It made it a modern city.

But within a few months,

water was to have a very different effect.

Less than a year

after this incredible technological breakthrough

disaster struck.

A storm hit and the flood waters of the rivers tore

through the building effectively bulldozing it.

(Dramatic music)

So, the buildings that would have been

originally here were completely washed away

in the flood of 1890.

This is the danger

when you're trying to harness the power of mother nature.

When it goes wrong it goes very, very wrong.

I can't imagine the level of devastation

after having achieved this amazing thing

of transmitting energy and electricity over long distances

to have that completely wiped out within a few months.

Following the violent storm,

repairs to the power station quickly got underway.

And soon it was powering what would be the final phase

in the development of this industrialised heartland.

A thriving papermaking industry emerged

that was among the first in the country

to use machines operated by electricity.

Over time, older buildings made way for modern papermaking facilities,

the derelict remains of which line the water's edge today.

At its height, the factories provided vital jobs

for around 2,000 workers.

But the manufacture of paper also came with a heavy price.

The early days of paper making was very toxic.

Sadly, a lot of that was dumped into the river in the late '60s

which virtually killed the fish population.

(Sombre music)

In time, the mills cleaned up their act and later lead the way

with recycled products.

But the writing was already on the wall.

In the end the spiralling costs of keeping up

with the evermore severe environmental legislation

and the stiff competition coming from cheaper products abroad

meant that the paper mill couldn't keep up, and closed.

So, the site represents really the history of america

tells the entire story from pre-white settlement

to current times.

And it's... it really is the story of america told in one single place.

(Dramatic music)

With almost 200 years worth of industrial development

still visible here,

this has been a place of almost constant change.

And today with work underway on plans to redevelop the site,

there's still plenty of life here yet.

People have always used the area

for what struck them as important at the time.

And in today's age the falls

are now merely appreciated for their beauty.

In the mpumalanga province of South Africa,

nestled at the foot of a mountainous valley,

is a set of structures with an incredible story to tell.

When you first sort of look

at this clearly some sort of abandoned town

but it's not like some small stage post town

in the middle of the outback.

There's a main street running through the middle.

There's houses, hotels, bars, church but it's not just one street.

This place is utterly sprawling.

We're way out in the remote countryside

so there must have been a good reason

for all these people to move here,

some incentive to get people to settle these hills.

(Intense music)

Lining the Ridge above are rundown buildings constructed

in a different style.

Perhaps these provide a clue as to why a community somehow grew

in this unforgiving terrain?

Around this place is some pretty industrial looking machinery

and that coupled with all the numerous buildings

this was clearly designed for processing something.

But what that was is not so clear.

They even got up in the hills.

You've actually got, looks like some sort of abandoned tram line.

And so, there was clearly something very important that

they wanted to move around.

But what exactly was being transported

and how does it connect to the eerie

preserved houses and empty streets below?

It was clearly in its day a booming town

but something went wrong and really rather fast.

Was there a really dramatic thing that happened

that killed off everyone?

Why is there nobody there?

It's a stunningly beautiful landscape

but when you look at it and its remote area,

you do wonder aside from the natural beauty,

why would somebody wanna live out here

and what would their livelihood be?

In the late 1800s

this was a place of discovery,

a new frontier which in time would be gripped by fever,

tainted by greed and touched by war.

19th century South Africa

was all about opportunity and exploitation.

So, although this place

was in the middle of a vast and empty landscape,

people flocked here in their thousands

from every corner of the globe.

But what valuable prize first drew people here

and why did they leave so suddenly?

The answer is to be found buried deep in the ground

and in the streams and rivers of the country.

It's not really actually clues in the landscape

that there's lots and lots of mineral wealth there.

So, in a sense you have to be kind of looking for it.

In 1886 fortune seekers began to descend on the African continent,

kick-starting one of the biggest land grabs in history.

But a decade earlier, the region had been the setting

for South Africa's first gold rush

and the story of how it was discovered

is the stuff of legend.

Back in 1873 there was a prospector

who was known as wheelbarrow Patterson

because he had bought his gear all the way from the coast

literally in a wheelbarrow over 1,000 miles.

Patterson did strike it lucky in one small stream

but he kept this finding to himself.

He didn't report it.

But he could only keep it secret for so long.

But pretty soon the word got out

and miners from all over began flooding into the area.

Almost overnight a makeshift camp sprang up.

Joseph mashego is an expert on the history of mining

in this area.

When prospectors arrive here,

there were no proper structures.

So, they used tents as accommodation.

Within months, 1,500 miners were working around 4,000 claims

all determined to find the most precious of metals.

Before long the ramshackle parade of canvas tents was replaced

by buildings with iron roofs.

In its heyday this was ground zero

for the great South African gold rush.

This is the ghost town of pilgrim's rest

and these are the rivers of gold that built it.

Very, very quickly, pilgrim's rest

became a classic boomtown, a gold rush town.

And the population exploded, you had saloons

and everything else associated with young men with too much money.

In less than a decade,

gold worth hundreds of millions of dollars today,

was drawn from the riverbed.

Now, when the prospectors arrive here,

they had no machines.

They had no chemicals.

Now how they separated the gold they only use water.

So, one of the classic ways of exploring for gold

is looking in rivers because rivers erode the landscape

and concentrate heavy things like gold in them.

The kind of gold that they were finding here

is what you call alluvial gold.

It means gold that's been washed out of the big ore veins

in the mountains.

The reward was unimaginable wealth.

But the search for gold also came with a big downside.

Wherever there's been a gold rush it has attracted adventurers,

you know, often reckless types.

But they're willing to gamble a lot and live through a lot of hardship

for this chance to literally strike it rich.

During such a gold rush, the environment is electric

but it's also dangerous.

People would fall into despair if their particular plot was barren.

They may, you know, may even be driven to suicide.

It was that sort of crazy environment.

Now, they suffered a lot, then they were alcoholic.

It's how they misuse their money.

Only 5% got rich and 95% were poor.

Yet trouble of a different kind was brewing.

In time gold from pilgrim's rest was to become involved

in a bloody conflict,

one that would result in the deaths of thousands.

At pilgrim's rest, the advent of the boer war

meant the mining industry pretty much shut down.

The second boer war began in 1899

and it was fought

between the British empire and two boer states,

orange free state and the South African republic.

The boers were of Dutch descent and they were fighting

for independence from British colonial rule.

Outmanned and outgunned the boers were forced into retreat.

But it was the gold from pilgrim's rest

that provided them a lifeline.

The boers took over the area

and a lot of the miners were forced to leave.

The boer army desperately needed to raise money.

Using gold from the mines a makeshift mint

was hastily assembled.

530 so called pilgrim's rest gold coins were struck

but before they could be used, the boers were forced to surrender.

(Intense music)

But this was just the beginning.

What was in store for pilgrim's rest was so much bigger

than anyone could have ever imagined.

Hunger for gold would eventually drive

technological innovation.

Although the mine's most productive days

were still ahead of it, the dreams of many were left in tatters.

Some of the different operations

mining for gold they merged

and they built a much more industrialised

mining operation that kind of took the place

of a lot of small groups out there with their picks and shovels.

That starts to explain the big machinery.

It starts to explain the sort of rock crushing equipment.

So, once you begin this mechanised mining operation,

you need a lot of power to run it.

The solution to this

was the Belvedere hydroelectric power plant.

And this became the largest at its time

hydroelectric power plant in the southern hemisphere.

We are sitting right at the bottom of the blyde river canyon

where the Belvedere power station is established.

We had electricity before england and France

when they were still using gas.

This impressive feat of engineering pumped out

over 2,000 kilowatts of energy.

Armed now with a constant reliable supply of power,

production at the mine stepped up a gear.

Real wealth of this area could finally be realised.

This tramline took the mining of this area

up to a whole new level.

It meant that huge amounts of iron ore

could be transported at one time

and with it the gold that's hidden within.

The main boom period for this mine actually

was 1913, 1914.

They were producing 112,000 ounces of gold leading to a profit

of 550,000 rand which you might not think is that much money

but in those days it was an awful lot.

But for pilgrim's rest, the industrial mining

that brought such prosperity was also the cause of its demise.

With the land stripped of its worth, gold production steadily declined

and the people began to leave the town.

Some amount of mining limped along until the 1970s

and then they shut down for good.

But the town didn't completely disappear

as is so often the case.

(Dramatic music)

In 1986 the settlement, now largely deserted,

was declared a national monument, a South African boomtown

built on gold now preserved for future generations.

People love to see these dramatic moments in history

and there's nothing more dramatic than the idea of a boomtown

and gold miners and all that romance

and you can still see a little bit of it

when you visit a place like pilgrim's rest.

In southwest england, in the county of somerset,

relics of a long gone era are hidden amongst the rolling hills

and green pastures.

So, here we are in the beautiful English countryside,

you know, surrounded by fields, miles from anywhere.

And it looks like nothing has ever changed.

You see this weird sort of train of trees.

As you delve further through the trees

you actually come to a waterway that leads

to an arch leading somehow into the hill.

The tunnel's been barred.

You can't get into it.

It's dark so you can't see what's down it.

What was the purpose of this?

What is it doing here and where does it lead?

A look at the surrounding terrain reveals other strange constructions.

So, moving away from this sort of mysterious tunnel

all of a sudden you start to come

across some other quite quirky things.

(Dramatic music)

Tucked in amongst the undergrowth,

you find these brutal, heavy, robust concrete structures

very deliberately placed

but completely at odds with the surrounding.

These appear to be from a different era entirely.

So, here we have this tunnel on one hand

but then we have this much later concrete structures

scattered around the countryside.

There's a link between them but what is that link?

What does all this have to do with the deadliest conflict

in history and the revolution that changed the world?

Nestled in the English countryside is a set of mysterious structures

that began life in the early 1800s.

It was a time when britain was at the centre

of the industrial revolution.

In the 19th century, it's a time of opportunity.

We're moving from this very agricultural

rural base to manufacturing setup.

And there is fortunes to be made.

In this period, the demand for resources was huge

and growing daily.

But it wasn't just about how much you could get.

It was about how fast you could get it

to where it needed to be.

The solution was a series of interconnecting canals

to link the country's main rivers.

The canal system in the UK really kicked things off.

Suddenly, there was a way to transport

these high-bulk low-value materials around the country,

export them around the world.

And the canals made that transportation possible.

By the early 1800s more than 2,000 miles of canals

had been completed.

David viner is an expert on the UK's pioneering canal network.

Ok.

So, we just arrived at a place called crimson hill

which is about halfway along the line of the old canal

that ran from creech just outside taunton to chard

and this was a serious bit of geography

they had to contend with.

If you look at the site from the air

you can see the canal just follow that line of trees

and it goes pretty flat for a while.

But then you get to this base of a significant hill

and that's a real obstacle.

And there's no easy way round this

so the engineering solution at a cost is to go through.

(Intense music)

This is the crimson hill canal tunnel.

I've just come into the entrance of the tunnel.

The first time I've been here so it's quite exciting.

It's fenced off to stop intruders.

Let's unlock the door.

Construction of this 13-mile long canal began in 1835.

It was the 5,400ft tunnel that presented

the biggest engineering challenge.

They dug down from the top of the hill

and then dug out towards each side and they did this one first

'cause if they couldn't overcome this obstacle

then the whole project will have fallen apart.

(Suspenseful music)

So, we're travelling through the crimson tunnel now.

I don't know when the last time somebody came through

because it's normally gated off.

This is really quite exciting.

It is in very good condition.

Water dripping through in places.

But the clock was ticking.

A brand-new invention came along

to threaten the future of britain's waterways.

So, in the case of the chard canal it was always at a disadvantage.

It was built late on in the canal period,

right at the end of the canal period.

And by the 1840s the railways were coming.

And the advantage of the railways is that they were much faster

and they could carry a lot more freight.

By the middle of the century, there were more than 6,000 miles

of railway track in britain

connecting more of the country than ever before.

Steam powered locomotives were quicker

and more cost-effective.

For the nation's canals the death knell had been sounded.

In the end, canals couldn't really compete.

It became cheaper to lay down railway lines than to dig canals.

After only two decades in operation, the chard canal was abandoned.

But that was not the end of its story.

After the heydays of the canal, the landscape just fell back

into its rural farming role.

But these brutalist structures that follow the line

of the canal mean that something else happened.

70 years after the last barge transported its goods,

the dangers of the 20th century's bloodiest conflict

saw the canal reopened and repurposed.

Following the evacuation at dunkirk in the second world war,

britain had to gear up to face

one of the greatest existential threats to it ever,

the possibility of a German invasion.

Defences had to be prepared.

But this is not the coast so why build defences here?

Out of nowhere

there's this great concrete structure here

which is a pillbox part of a second world war defence line

and it's in an absolutely commanding position

and it's... there's another one over there

so they could control the line of fire in two different directions.

This is the taunton stop line,

a continuous 48-mile antitank structure that runs

between the Bristol and English channels.

It was to form a crucial part of the nation's defences

should Germany have invaded.

When they were designing this defensive line,

they wanted as far as possible to take advantage

of the natural obstacles.

So, rivers, waterways like canals and railway embankments

or anything that proved an obstacle.

In just a matter of months, 18,000 pillboxes

and lines of so called dragon's teeth

were constructed at vital positions around the UK.

Here, they were intended to defend the crucial southwest corridor.

Fortunately, the brave men stationed inside them

were never called into action.

They did the best they could with the time

they had and the materials on hand.

But in the end, these fortifications were not going to stop

a determined enemy for very long.

If you were stuck in one of these pillboxes,

it was likely gonna be your last stand.

By 1945, with the threat of invasion long gone

and Nazi Germany beaten, the defences became redundant

and they quickly fell into disrepair.

This is not state-of-the-art defensive engineering

but what it is, is a very quick, a very cheap solution.

It gives heart to the population that they're being looked after,

that they're being protected.

Today they still survive as a visible reminder of britain's

and Europe's bitter struggle against tyranny.

(Dramatic music)

Now, they are abandoned crumbling ruins.

Many remind us of dark times

but some were once beacons of hope and progress...

Lasting testimonies to human imagination,

enterprise and spirit.

(Theme music)

Captioned by ai-media ai-media. TV