Original subtitles

Narrator: Rusting relics that helped build america.

The structure was home to revolutionary technologies,

ones that would go on to help save countless lives.

Ancient technology in a lost world.

It's like being in a sundial,

these guys are mathematical geniuses.

A Welsh island transformed into a magical attraction.

They wanted to make it their home

but they also had something else that they were bringing along

which was a little bit unusual.

(Suspenseful music)

And a training ground for elite communists.

The men who passed through here went on to prominent positions.

(Dramatic music)

Decaying relics.

Shadows of lost worlds.

Ruins haunted by the past,

their secrets waiting to be revealed.

(Dramatic music)

(Upbeat music)

At the end of a blustery beach in wales

there's an imposing ruin a jagged outcrop.

You sort of at this idyllic British beach.

And you look over and you've got this rocky island.

During high tide, this place is entirely cut off,

trapping anyone on the island.

As the tide drains away,

slowly the bottom steps of the staircase are revealed.

Battered by the elements, it's a daunting place.

When you've made it all the way to the top,

you arrive at this huge solid steel door,

secured by a big bolt

and it makes you wonder what's inside.

It's a sort of place as a kid you think

it would be really fun to get on to

but also you'd be quite worried

about it being some kind of strange lair in there.

The locals remember less permanent structures

added to the roof of the fort.

These were very basic wooden structures

covered with wire netting.

They also had some open-air cages up on the top.

Who or what was living here that had to be kept on the island

with the help of this high tide?

(Eerie music)

Local conservationist Ginny batt

knows more about the island than most.

I remember this bridge, when I was a child,

was wooden slats and rickety and wobbly.

And you could hear the waves crashing below you like we can now.

I'm not quite so sure whether or not this bridge is more scary

than the one that I used to cross as a child.

And I didn't walk slowly like this over that one, I used to run.

(Birds chirp)

This windswept outpost sits at the junction of the Celtic

and the Irish seas.

The island is magical,

you know it's got secrets, got lots of history.

The little promontory itself it about 600 odd feet in one direction

200 in the other

and it's a limestone bit of rock,

very easily weathered away but with water

so you get all of these sea caves.

Humans have lived here for 1,000 years

beginning with religious hermits who used the caves.

The island got its name after a chapel was built there

dedicated to Saint Catherine.

But traces of the chapel are long gone.

No one's lived here since Ginny batt and her parents left.

I have lots of little memories and little snippets

of things that happened here while I was a child.

Came up here a lot,

probably not on to this bit 'cause it's quite dangerous

but definitely up onto the roof

and over to here, this area here.

You can see all of tenby,

the coast,

caldey island,

all the way over to pendine sands

and on a good day, gower.

It's amazing.

(Water crashing on rocks)

The batt family once lived in the enormous concrete structure

that dominates Saint Catherine's island.

When you look at the structure, the purpose is clear,

this is a fortification that has fallen into disrepair,

there's more here than meets the eye.

In the mid-19th century,

the British built a series of defensive fortifications

along the coast.

It was built here because of its prominence

and its proximity to other ports in the region.

But even before the fort was finished

international relations had improved

and by 1901, it had been mothballed.

But the story didn't end there.

We moved on to the island in 1968.

I was four years old.

So it's great to be back.

Yeah, it's lovely. It's home.

The batt family were the last of a series of private occupants

to take over the fort.

The first owner had decorated the interior with no expense spared.

But by the time Ginny's family arrived,

the strange fortress home was already a wreck.

(Eerie music)

I find it very wistful, coming back here.

You know, it's, there's been through lots of phases

and it's been left to rack and ruin.

But back in the 1960s

it was perfect for what her parents had in mind.

They saw st Catherine's island

and discovered that it was up for rent.

They needed somewhere to live but not just for themselves,

in tow, they had something quite unusual,

which meant that the only place suitable for them to live

was the fort,

out on those craggy rocks down by the beach.

Ginny's parents had long dreamed of opening a zoo

and had already started collecting animals.

They bring in a lot of exotic animals

and they open a zoo in this abandoned coastal fortress.

You climb up the stairs

and you're greeted by the howls of monkeys,

I mean that's got to be the last thing you'd be expecting.

I don't think anybody had ever seen anything like this.

There was nothing conventional about the batt family life here.

When we arrived the tide was in

and dad had to paddle over in a metal bath to collect us,

so that's one hell of a way to actually arrive in your new home

is in a bath,

so that was quite an interesting way to get here.

In march 1968,

st Catherine's zoo opened

and it was a big hit with the locals.

And it was very popular, you know,

there were queues across the beach of people coming,

coming up here

but I think people were intrigued really

about how my parents managed to set up something like a zoo

on an island surrounded by a tide you know,

on an old fort with no power and no water.

There was a surprise behind every door.

We used some of the rooms for living in

and the other rooms were used for animal displays.

We had a pet room, where there were rabbits and Guinea pigs and chicks,

another room had little finches and little marmosets and things.

And out at the back,

in some of the darker corridors around the back,

there were a nocturnal room

and there were reptile rooms,

'cause my father was really into reptiles.

The zoo was filled with all sorts of animals

from badgers and foxes, to bats and birds,

even exotic monkeys and alligators.

(Mellow music)

Ginny and her family shared this place

with more than 100 animals,

parts of the old fort had to be creatively repurposed.

You had some open-air sort of cages up on the top

where the gun turrets used to be.

This is my favourite place.

So up here there were aviaries all the way around on both sides.

And there were things like monkeys and hawks,

lots of birds of prey,

and then over the other side there was porcupines

and then somewhere down below there was a monkey.

Ginny's upbringing was certainly not typically Welsh,

in fact, it was more like a fairytale.

Tucked in little places like on the stairs as you go up

there's a little hole in the wall and there were tree frogs in there

so you know, there were things in little, quiet little places.

One can only imagine being a, being one of the children

living in this, in this family,

you've got this wonderland that, that's your house

which is a little zoo and you've got all these animals.

It must have been a crazy and wild time for them.

For Ginny, every day bought a new adventure.

There was a spider monkey.

I remember it pinched an old man's false teeth

'cause he was making funny faces at it.

It's a really strong memory.

But for Ginny's parents,

life at the fortress zoo was becoming a struggle.

You have to remember that, you know,

we walked up those slippery, stony steps

and everything was carried up there, you know.

The animals, the water, the food,

absolutely everything was actually carried up there.

It's certainly charming

but there are inherent difficulties living on a tidal island like this.

Ginny's parents struggled on

but when her mother fell pregnant unexpectedly,

life in the isolated ruin was no longer viable.

We moved off the island

because my mum was expecting my brother

and living on an island where there's no electricity

and there's no running water,

wasn't ideal bringing up a little baby.

Then we lived on here for two, maybe more years,

and then moved off the island and still ran the zoo.

Eventually running the zoo became too much for the batt family

and they handed on the Baton.

It was not the end of the line for the zoo

but as new owners took over, things started to change.

Monkeys would escape their enclosures

and climb down the side of the island

and end up marauding around the beach.

But by the mid-1970s,

britain had passed new laws

that required dangerous wild animals to be kept in large enclosures

and the strange configuration of st Catherine's island

was no longer fit for purpose.

In the end, the zoo was shut down for animal welfare purposes

but the animals themselves were actually rehoused elsewhere.

The fortress zoo was left to rot.

You can't argue with the grandeur of the location.

How well suited this place is to house these animals?

Well, that's another question.

(Eerie music)

There are plans in the works to refurbish the fort a bit,

turn it into more of a tourist destination

but those are still in the future.

The monkeys that used to roam the beach

are now just a distant memory of a bygone era.

And Ginny is left with memories of that special family time.

It's an abandoned, beautiful building

and it should be open to the public

to see what an amazing structure is.

I was lucky, I lived on here.

(Dulcet music)

(Pacing music)

In the lovely Croatian countryside lies a strange-looking building.

We're in a beautiful lush corner of the Balkans,

right along the frontier of Croatia and Slovenia,

a beautiful spot once prized for its good farmland.

But this building does not fit in with this bucolic landscape,

its sharply angular with these steep sloping sides.

It's great size seems to make little sense.

As you walk in there's this huge lobby area

and there's also this amazing bar area with fixed wooden stools.

You're struck by the sheer extent of the place and long corridors,

dormitories on either side, big conference rooms.

There's a huge room that seems like a cinema

it's dark and kind of oppressive.

It's completely rotted out

with seats that are just destroyed by water.

Inside the derelict building there's also some kind of library.

The ground is littered with books and pamphlets and other detritus.

It's really interesting to look at what's there now

because you do see scattered amongst it,

volumes of marxist thought.

These books could be key to understanding

what this place once was

and why the world no longer has any use for it.

It's almost 50 years

since branko pratengratzer first set foot in this building,

which dominates the tiny Croatian village of kumrovec.

(Speaks Croatian)

(Indistinct chatter)

Back then, Croatia was part of

the federal people's republic of yugoslavia

which was formed at the end of the second world war.

This union of fractious Balkan states

was headed up by communist leader josip broz tito.

Tito's brand of communism, which was known as titoism,

had a pragmatic approach

and it didn't try to achieve the level of purity

that the ideology coming out of the Soviet union possessed.

Tito realises that there's a real, you know,

lack of solid theoretical education inside yugoslavia,

people all say, "oh we're communists"

but they don't understand why they're communists.

So tito wanted to set up a school

where they would learn communist theory

and explain why communism was necessary for yugoslavia.

This is the josip broz tito political school.

But why was it built in the back woods of Croatia?

The town of kumrovec was chosen

because it was josip broz tito's birthplace.

And in the 1970s

tito undertook to transform kumrovec

into a centre of yugoslavian political thought and education.

(Dramatic music)

Tito's political school opened in 1981.

Branko and the other students would learn their leader's philosophy

on keeping the peace in the Balkans.

And so it was a school that was meant to deepen people's knowledge,

it was one of the most prestigious schools of political learning.

(Speaks Croatian)

Yugoslavia's brightest minds were trained here.

(Speaks Croatian)

The students had privileged access to resources

that were denied to many in yugoslavia at the time.

(Speaks Croatian)

(Speaks Croatian)

(Suspenseful music)

The men who passed through here went onto prominent positions

in the Yugoslav political apparatus.

But the school students would learn about tito as a former leader.

Tito died a year before the school opened

and with tito's death this idea of a yugoslavia united

under the rule of this communist strong man started to decline.

And the school was also beginning to wither.

With tito gone,

yugoslavia's member states no longer wanted to fund his political school

but like yugoslavia itself it managed to survive another decade.

After the school shut in 1990

it was first taken over by the interior ministry

and subsequently by the defence ministry.

(Speaks Croatian)

This is a time when yugoslavia's breaking up,

it's being torn by these ethnic fishers between its groups,

the Serbs, the croats, the slovenians and others

and particularly in Croatia.

In 1991, a bitter war broke out.

(Tense music)

Things get rapidly worse when the civil war spreads into Croatia.

There's a huge battle in a place called vukovar,

the Serbs take it,

the Croatian population then migrates back here

and they use this political school as essentially a refugee camp

during this Yugoslav civil war.

All of these dormitories that were created for political cadres

are now used as bedrooms for refugees.

When the refugees finally left in 2003,

the Croatian authorities no longer wanted to celebrate titoism

and the school fell into disrepair.

(Foreboding music)

(Speaks Croatian)

This building and what happened in it

influenced the minds of hundreds, perhaps thousands,

many of whom still occupy positions of power in the former yugoslavia

so its influence continues to live on

even after the building itself has been abandoned.

In a suburb of New York City,

there's a boarded-up building with an illustrious past.

(Suspenseful music)

There's this well designed red brick building,

it looks pretty self-contained.

It could be a factory

or maybe even some kind of old victorian workhouse

out of a dickens novel.

There was a lot of care that went into these beautiful arches

and lovely brick design

so there was obviously something that was really important here.

It's the surrounding geography that offers some clues.

The rivers actually run on both sides of all of these structures

so these structures essentially formed their own little island.

It looks like some of the areas are flooded,

almost as if the site was designed to be flooded.

The building's interior is even more baffling.

There's this chaotic industrial mix of things,

you have these pipes

and machines that seem to be all over the place.

Everything appears oversized,

this place was the target

of an awful lot of ambitious engineering.

This facility was at the vanguard of technology

at a time when these advances really could save thousands of lives.

(Tense music)

Local historian Elaine gold

explains why it's the two rivers that are crucial

to understanding why the building was established in the first place.

This was a mill site from even pre-rev war era,

it had several aerations as a mill,

it would have been a flour mill, sawmill

then it was purchased specifically for the purposes of this facility.

In the late 19th century,

there was a huge increase in population in america

and this area felt the effects more than most.

Hackensack New Jersey is pretty close to New York City

so as the economy boomed after the civil war,

the population here boomed as well.

There are successive waves of immigration

and these people are filtering to big cities like New York

and hoboken, New Jersey

and they're settling in the outlying areas.

The number of people living here more than doubled

in the first decade of the 20th century.

It was all driven by facilities like this one.

The new milford plant of the hackensack water company.

It was built as a result of a contract

that was signed with the city of hoboken

and the hackensack water company to provide water to that city directly.

It meant that people would no longer have to collect their water

from local Wells or rivers.

The purpose of this facility was to pump water from the hackensack river

and to service the city of hackensack

as well as the city of hoboken.

The steam-powered pumping station siphoned water

directly from the river

and sent it straight on to the local population.

We're inside the 1882 pump house

so this was the first pump house constructed on this site.

The system contained large pumps, it could pump a lot of water

but demand kept increasing.

It was the constant race to build bigger and better pumps.

This is the later part of the additions

to the hackensack waterworks

as the service area expanded and demand increased.

Height was added to accommodate these pumps

because they were the equivalent of a three-storey building.

In 1911, the company installed pump number seven,

this was a vertical high service pump

and could pump as much as 20 million gallons every single day.

With each rotation of the pistons,

that was 6 million gallons of water pumped.

What you're really seeing here

is not only a chronology of construction

of the actual building itself,

you're also seeing a chronology of techniques in pumping.

You can almost imagine how loud this place would have been

during work time,

I mean, you would have the clinking of machinery,

the hissing of steam

and the sounds of all of these pumps running at capacity.

This plant was operating at a phenomenal scale.

(Foreboding music)

As pumping power increased,

problems with the water itself began to appear.

In the early years of the plants operation

there were lots of complaints about the quality of the water.

They were getting reports that you know,

the water smelled of old fish,

that the, it was sometimes the colour of milk

when it would come out

and because the water levels were low up here

eels were pumped out of the hackensack river here,

sat in the basin and then were filtered through

and pumped down into the, into hoboken

and end up in the water system down there.

The complaints soon bought the authorities to hackensack.

So the board of health actually went upstream

to investigate what types of things were bordering this river

and they found outhouses and stagnant ponds

and chicken yards and pig farms

and they realised that all of this excrement and material

was making its way into the river.

There were other contamination problems to contend with,

an influx of immigration caused massive overcrowding

in and around New York City area.

In every major city in history, diseases have spread

because of contamination of the water.

Cholera, typhus and other diseases killed an enormous number of people.

The hackensack water company had to figure out

how to prevent this from happening to its water supply.

(Suspenseful music)

It's really impossible to overestimate how important

water treatment was to Americans at this time.

In 1900, more than 44% of deaths

were attributed to waterborne diseases

or other types of infectious diseases.

The company had to break new ground,

the plant needed to become more than just a pumping station.

So in 1903

construction began on two big settling ponds

or coagulation basins.

The process of the water travelling from the river through the pumps

to the coagulation basin filtered out a lot of the plant growth

that would have been coming naturally from the river.

This removed the bulk of the solid particles

but it was the unseen bacteria in the water

that was the real killer.

The laboratories here would come up with a solution

and these processes would be used all around the world.

Another building here reveals this revolutionary treatment process.

This is the filtration building,

water would have travelled through sand pits

and filtered down into holding tanks

and then been pumped out for general public use.

Unseen bacteria in the water could prove deadly,

so in 1908,

the hackensack plant became one of the first in the us

to use chlorine to disinfect it's water.

But it didn't really do anything to solve the issue of the bad taste

and odour of this water.

Another process had to be added.

The chief scientist for the hackensack company

knew that activated carbon had the ability to remove contaminants

in a process called absorption.

When any form of carbon is heated to a high temperature

it leaves a very fine powder called activated carbon.

It would remove a lot of the contaminants

that caused bad odour and bad taste.

In 1931, this water treatment plant

was the first to use this activated carbon in a municipal water supply.

By 1943,

there were over 1,200 water treatment plants

around the world using this technique.

Over the following decades, the waterworks continued to expand.

By the 1960s,

the hackensack water company was actually putting out

a maximum output of 100 trillion gallons of water per year.

But hackensack's new milford plant

eventually became a victim of its own success.

To meet the ever-increasing demand for clean water

the company had to build a larger facility

that simply wouldn't fit on the original site.

In may of 1990,

all treatment and pumping at the new milford plant had ceased.

(Dramatic musical sting)

Unglamorous buildings like this are often overlooked

and underappreciated.

The idea that you can flip on a light switch and get light,

you can turn on your faucet and get clean water,

but these things were really revolutions

and they demanded an enormous amount of hard work

and creative engineering

on the part of the people who really made this stuff happen.

Elaine gold wants to commemorate hackensack's leading role

in building the modern world.

We are eager to reactivate the site

in a combination of both museum and public park.

This building really is a testament to what can be achieved

when you trust science and technology

and put people's health and wellbeing first.

In Mexico,

a great collection of ruins juts out from the dense jungle.

(Dulcet music)

You've got to break through that rainforest canopy

and only then can you start to see signs of human habitation.

As you explore further

it becomes apparent that this was once a fair-sized city.

Thousands of people,

tens of thousands of people interacted here day by day.

But when they left, the forest returned.

(Drum music)

The clues here hint at a complex society.

All over this place, you can find these epitaphs

but it's almost impossible to decipher them.

This remote overgrown place lay hidden for centuries

and even today it's slow to give up its secrets

but all around is evidence of sacrifice,

violence and conflict.

When did the last person leave and why did they go?

(Tense music)

Today, archaeologists like Adriana Velazquez morlet

decode the secrets of this place

which was abandoned more than 1,000 years ago.

It's the work of the ancient Mayan civilisation.

(Speaks Mexican)

Despite its size

the city wasn't rediscovered until 1931

when an American biologist spotted it from the air.

(Pacing music)

This lost world is calakmul,

one of the largest and most powerful Mayan cities.

(Speaks Mexican)

As the early archaeologists cut through the thick jungle

they stumbled upon calakmul's pyramid,

the highest in the Mayan world.

(Speaks Mexican)

(Speaks Mexican)

This king's name translates to claw of fire

and at the age of 36, he took possession of the throne.

When claw of fire took over,

he inherited the really rather large and powerful snake kingdom.

This kingdom, this snake kingdom

extended for miles around this place.

Claw of fire ascended to the throne in 686 ad.

A series of engraved stelae give archaeologists vital clues

to understanding more about this mysterious

and once-mighty kingdom.

(Speaks Mexican)

Further ruins unearthed here

reveal more about how the calakmul kings governed their people.

Two structures work in tandem to track the sun

and identify significant dates in a sophisticated calendar.

(Speaks Mexican)

You are effectively in an enormous astronomical observatory.

These guys are mathematical geniuses.

But unlike any other Mayan discovery,

the murals of calakmul gave archaeologists a unique insight

into what went on here.

Some of the ornate murals and decorations

that are inside these structures,

they're depicting the everyday life of ordinary citizens of calakmul.

(Speaks Mexican)

They help to decode one set of calakmul's ruins

that previously made little sense.

(Speaks Mexican)

The Mayans used trade to keep the peace

along with a more savage form of diplomacy.

(Speaks Mexican)

This game was very energetic,

very vigorous, very colourful...

(Chuckles) ..And quite possibly deadly.

Yet despite its violent nature,

the Mayans used the game to prevent conflict.

But in the late 1990s,

archaeologists discovered something troubling

on the outskirts of the ruins.

There is a defensive wall built around this place,

you don't build a wall like this

unless you're really trying to keep people out

'cause they are coming to kill you and burn your town.

This wall is there to stop this city from going up in flames.

For more than 100 years

claw of fire's predecessors had consistently won battles

against calakmul's main rival,

the city of tikal.

(Speaks Mexican)

(Speaks Mexican)

And in the late seventh century in calakmul,

the young claw of fire was flexing his muscles.

His opposite number was another young gun,

the king of tikal known as god that clears the sky.

They were both relatively young rulers when they came into power

and they had a lot to prove

but they also potentially had quite a lot to lose.

In the year 695 ad,

the two faced each other in battle.

These two cities are going to try to destroy one another.

Calakmul had won many great victories over the years,

but this time claw of fire's warriors were soundly beaten.

(Speaks Mexican)

Archaeologists now believe that claw of fire

lived out the rest of his days in calakmul.

The city itself continued to grow

but it never ended its rivalry with tikal

and in the eighth century, the population began to decline.

By about 900 ad, it had been abandoned.

(Suspenseful music)

Archaeologists are still convinced

that many of calakmul's mysteries remain hidden by the dense forest.

No doubt when this place was inhabited,

the forest was pushed back for agriculture, commerce

but when they stopped it grew through the very stones

that they had cut to make this their place.

This place no longer belongs to people,

this place belongs to the rainforest.

But there is hope that the jungle will one day give up its secrets

and finally reveal how claw of fire's snake kingdom

met its end.

Captioned by ai-media ai-media. TV