Original subtitles

*

Narrator: five strange, Circular structures

Mysteriously deserted...

Gough: everything is curved.

There's no place where You can go and not be seen.

*

Narrator: ...An abandoned wall of concrete

Perilously wedged Between mountains...

Something so impressive In the landscape

To be built Is a real engineering feat.

Narrator: ...And an american escape route From nuclear armageddon.

Dickrell: you can envision Terrorized people

Trying to avoid A nuclear explosion

In a large metropolitan area.

*

Narrator: once, they were some Of the most advanced structures

And facilities on the planet,

At the cutting edge Of design and construction.

Today, they stand abandoned, Contaminated,

And sometimes deadly.

But who built them? And how?

And why were they abandoned?

And why were they abandoned?

-- captions by vitac -- Www.Vitac.Com

Captions paid for by Discovery communications

*

*

On the cuban island Of isla de la juventud

Sprawls a group Of peculiar structures.

*

*

Laid out like Five spots on a die,

These circular giants Are 174 feet in diameter

And tower over a 4-million Square-feet open plain.

*

If you were flying over The island and you looked down

And saw these five Yellow, circular buildings,

You would think, "What, is this Some sort of industrial beehive?

Is it a power plant? No, it's not really shaped

Like a conventional power plant.

Like a conventional power plant.

What is it?"

Narrator: The four outer buildings, Each 98-feet high,

Consist of six levels,

Yet inside, There are no floors --

Only a colossal empty space.

Light pierces The dank, grim interior

Through 465 Rectangular openings.

Had a pretty sinister reputation Amongst local residents.

And the conditions inside Were just atrocious.

And the conditions inside Were just atrocious.

Narrator: The most bizarre feature Is a short lighthouse-like tower

Standing in the center Of each building.

When you walk inside, you're Instantly struck by the fact

That there are No straight corridors.

Everything is curved.

You are constantly in view From somewhere else.

There's no place where You can go and not be seen,

And that was all by design.

Narrator: What happened on this remote Island in these odd structures,

Narrator: What happened on this remote Island in these odd structures,

And why was this site abandoned?

*

In the 1920s, cuba experiences A period of economic development

Against a backdrop Of political corruption.

Cuban president gerardo machado

Is determined to stay in power At all costs,

But to do this, he must Maintain ultimate control

Over his political opponents,

Not only physically But also psychologically.

Not only physically But also psychologically.

The solution for This dictator's total domination

Is the incredible island complex Presidio modelo,

Cuba's "Model prison."

Gough: It was created and conceived By a cuban dictator

Who drew upon An 18th-century social reformer

Who's whole ethos Was that behavior

Could be modified Via surveillance.

Narrator: Though originally intended as a Tool to rehabilitate prisoners,

Narrator: Though originally intended as a Tool to rehabilitate prisoners,

Surveillance here comes In the form

Of an oppressive Observation tower

At the center of the structure,

Which is key To the building's design.

You have a central Observation tower,

And then you have A circular structure

That surrounds that tower, which Is where all the cells are,

And the idea is that all The prisoners in their cells

Are not really sure whether The guards are looking at them

Or looking at Their neighbor downstairs,

And so they have to be on their Best behavior all the time.

And so they have to be on their Best behavior all the time.

That design inside the prison

Certainly feels Quite menacing to me.

That central tower With guards who, theoretically,

Then can be observing What's going on

In all of those prison cells At any time --

I mean, it certainly Feels quite big brother,

Something you might have read In george orwell's "1984."

Narrator: construction begins In 1926 using inmate labor.

As they complete each building, It is populated.

And these structures Are not just designed

And these structures Are not just designed

To create paranoia Amongst the prisoners,

They also have an unexpected Engineering benefit.

This philosophy of prisoner Observation actually led

To a very interesting Structural advantage,

And this advantage is the fact That having a circular wall

Going all the way around meant

That there was an inherent Stiffness in the structure

That meant you don't need To put intermediate floors in

To keep the structure stable.

Narrator: By the 1930s, presidio modelo Is fully operational.

Narrator: By the 1930s, presidio modelo Is fully operational.

Each building contains 465 cells That house two inmates,

All of which face inwards Towards the central guard tower.

It has a total capacity Of over 3,000 inmates.

But most incredibly, There are no cell doors.

The architecture itself Affects, shapes,

And enforces the behavior Of those in prison.

Translator: The tower was to control The prisoners inside.

Translator: The tower was to control The prisoners inside.

If there were any discussions, We'd say,

"Hey, there! Shh! Watch it!"

And they would.

The tower was to maintain order.

Narrator: Unseen by the prisoners,

Who never know if and when They are being watched,

The guards enter The observation tower

Through a 98-feet-long Underground tunnel.

Hidden from view, The guards keep an eye

On the prisoners Through narrow slits

In the top of the tower.

In the top of the tower.

You're constantly being watched,

Not only by the prison guards From the central tower,

But other prisoners whose cell Is only a few feet from yours.

There's no privacy whatsoever,

And it must have generated A whole lot of paranoia.

Narrator: the large open space Within each building

Makes surveillance easy, And the result is

That the inmates increasingly Police themselves.

Even at meal times within The shorter central structure,

There is no respite from The watchful eye of the guards.

There is no respite from The watchful eye of the guards.

You would think That leaving your cell

Where you're constantly Under surveillance

And going for a meal Would be a nice experience

Of chatting with Your fellow cellmates.

Not at all. You went To a building that was called

"The hall Of the 3,000 silences,"

And it was aptly named because You weren't allowed to speak.

Imagine how oppressive That would be --

You're being watched All day in your cell,

And now you're having a meal And you can't even speak.

*

*

Narrator: ironically, Its cutting-edge design

Originally conceived To rehabilitate convicts

Earns presidio modelo A reputation for horror.

And the prisoner relies On more than watchful guards

To keep its inmates Under control.

There are all sorts Of legends about the prison,

Including the fact that there Were crocodiles in the ponds

And lakes on the perimeter Of the prison itself.

Translator: When this was built, there Were crocodiles living there,

Translator: When this was built, there Were crocodiles living there,

And the prisoner who escaped,

If he didn't get caught running,

He would be taken by them When he got there.

No freedom -- that was it.

*

Narrator: but will The architecture of paranoia

At presidio modelo be enough To keep the prisoners in line

And maintain A dictatorial grip on power?

And why was The prison abandoned?

*

Narrator: off the cuban coast On isla de la juventud

Sprawls cuba's abandoned "Model prison," presidio modelo.

After multiple regime changes,

Its terrifying approach to Imprisonment works for 27 years.

But then, in 1953, Its most notorious inmate

Enters its doors.

Enters its doors.

The communist revolutionary Fidel castro

Serves two years here

For attempting to overthrow The ruthless dictator

Fulgencio batista.

Seeing the psychological success

Of the jail's effective design Firsthand,

Castro realizes The potential power of paranoia

When he overthrows batista In 1959

To become president of cuba.

*

When he comes into power, He doesn't, you know,

Destroy the place. He doesn't knock it down.

Destroy the place. He doesn't knock it down.

No, he sends His political opponents there.

I think that's quite rich.

Narrator: for eight years, Castro uses presidio modelo

To bury his enemies.

But his political prisoners Begin to put up resistance

And pose serious security And political risks.

There is a dramatic plan To get rid of the prison

Using the underground Guard tunnels.

There was actually a plan To blow up these structures

Using that tunnel by actually Packing it in with explosives.

Using that tunnel by actually Packing it in with explosives.

And thinking about The sheer size

And scale of these structures,

The fact that they had This inherent stiffness

Because of its shape,

I think it would have Been quite difficult

To actually bring That structure down.

Narrator: Dynamite may not be able To destroy presidio modelo,

But castro does.

The prison has a capacity For 3,000 inmates,

But he packs it With double that number.

Bell: something that was Originally designed to house

Bell: something that was Originally designed to house

Up to 3,000 prisoners

Was now housing anything From 6,000 to 8,000 prisoners.

Riots were commonplace, Fights, unsanitary conditions,

And the place was just hellish.

Narrator: the measure Of over population backfires,

Encouraging further resistance From the inmates,

Eventually leading To the prison's demise.

Cramped, dirty, and overcrowded, Cuba's model prison

Is forced to close its doors For good in 1967,

Is forced to close its doors For good in 1967,

And castro's enemies are Dispersed to other prisons.

It just stops to function,

And it's a little bit Dilapidated anyway,

But the political climate Had changed,

And it no longer Had a purpose to serve.

Narrator: the unique design And function of the prison

Makes the buildings virtually Impossible to be repurposed,

And after 41 years Of oppression and paranoia,

They are abandoned.

Now the gigantic, Circular cellblocks

Now the gigantic, Circular cellblocks

Of the presidio modelo

Are decaying shells And stark reminders

Of cuba's political turmoil.

As symbols, they demonstrate

The groundbreaking Architectural design

Could not only Shape human behavior,

But also reveal The limits of social reform

And how easily it can backfire.

Today, the prison is a museum,

It's a school, It's a research center,

And that's about right Because what it really was,

Historically -- I think we look back at it

Historically -- I think we look back at it

As an innovative attempt At social reform.

It was all about surveillance,

And actually it was Quite ahead of its time.

*

Over 2,000 miles away Across the gulf of mexico,

A barren landscape Hides an enigmatic enterprise

Of forgotten engineering.

*

High above los angeles Is a closed-off road

High above los angeles Is a closed-off road

Winding 900-feet up In the san gabriel mountains.

It leads to a mysterious masonry Arch over 20-feet high,

Driven into its slopes.

But what is this an entrance to?

When you first see These entrances

Opening up on the sides Of the mountain,

You can't fathom Why the effort was gone

To build these huge, Great, big tunnels.

For me, you'd expect to see Some kind of railway or a road

Or something coming out of it, But none of that's there.

In fact, it becomes Quite mysterious.

Narrator: The light at the end of the Tunnel shows that this structure

Narrator: The light at the end of the Tunnel shows that this structure

Runs for 1,000 feet Through the mountain.

As you're standing there, You appreciate

What an impressive feat Of engineering it is

And how difficult It would have been to have made.

The interesting thing is There's a lot more to this story

Than meets the eye.

Narrator: why did someone Go to the trouble of building

This immense structure Through a mountain

And why was it abandoned?

And why was it abandoned?

In the 1950s, The threat of the cold war

Looms over a paranoid america.

The nation fears Not only an invasion,

But nuclear attack From the soviet union.

L.A.'s many aerospace facilities And military bases

Make the city a prime target.

America's early warning systems

Can recognize potential threats Hours before impact.

But in that small window Of time,

How can The authorities save

How can The authorities save

The then population Of nearly 2 million?

L.A. Authorities began to Wonder, "How would we evacuate?"

In the 1950s, There might have been 20 minutes

Or half-an-hour's warning

Of an impending nuclear attack On los angeles.

Any evacuation For the people of los angeles

Had to be prepared in advance.

man: in this trouble stage of the atomic age,

our very lives may depend on always being alert.

our very lives may depend on always being alert.

Narrator: if the soviets Strike los angeles

With nuclear weapons,

A credible escape plan needs To be in place for its citizens.

To get out of los angeles,

You've got To get through the hills

And the mountains And out the other side.

That means either twisting And turning through canyons

Or tunneling right on through.

Narrator: so, a 25-mile shortcut Is devised

That's designed to speed The city's residents through

That's designed to speed The city's residents through

The san gabriel mountains Via multiple tunnels

To safety of the mojave desert.

*

This path to safety Is shoemaker canyon road,

Better known As "The armageddon highway."

The armageddon highway Would work in premise --

The entire population Of los angeles

Would get in their cars And exit away from the city

And the eventual destruction That was happening.

Corum: this was part Of the culture at the time,

This fear that the other guy has A technology and can strike us,

This fear that the other guy has A technology and can strike us,

And we need to have some kind of Way to protect ourselves.

*

Narrator: Will shoemaker canyon road Work as an escape route

From nuclear fallout In los angeles?

And why was it abandoned?

*

Narrator: in the 1950s,

Gripped by cold war paranoia And desperation,

Los angeles authorities

Order the construction Of shoemaker canyon road,

With multiple tunnels Driven through the solid rock

Of the san gabriel mountains.

Once complete, they're designed To form a costly

But potentially vital evacuation Route high above the city.

Given the cold war in 1950s --

Given the cold war in 1950s --

Everyone was afraid Of nuclear war,

And in that, the response --

The government was to drill A hole though a mountain

Such that the population Of los angeles

Could escape Given all-out nuclear war.

One soviet nuclear weapon air Bursted over los angeles

Could kill more people Than were killed

In hiroshima, nagasaki combined.

Narrator: but carving a road Through a mountain of hard rock

Narrator: but carving a road Through a mountain of hard rock

Is difficult At the best of times.

And in the volatile region Of the san gabriel mountains --

With severe heat in the summer Avalanches in winter,

And the continuous Threat of landslides --

The challenges are All the more extreme.

To hold up In this harsh environment,

Interlocking steel beams And molded concrete

Are needed to shore up Critical stress points

Of 1,000-foot-long tunnel As construction starts in 1956.

Of 1,000-foot-long tunnel As construction starts in 1956.

You would have thought that A project of this importance

Would have warranted Professionals,

But what they got instead Was a chain gang.

I mean, they literally asked The inmates of nearby prisons

To go up into the mountains, Build the road.

I mean, not only was their heart Probably not into it,

But they didn't have The skill sets.

Narrator: with unskilled workers Struggling

To cut through solid rock,

The two-lane escape highway Makes agonizingly slow progress.

The two-lane escape highway Makes agonizingly slow progress.

This 1,000-feet tunnel Takes five years

And is only completed in 1961.

Dickrell: to be inside of it,

You can almost envision Terrorized people

Trying to avoid A nuclear explosion

In a large metropolitan area.

Bell: The fact that they were prepared

To blast their way Through these mountains

Just shows that level of panic And urgency that was felt

To give the people of a major U.S. City a means of escape

And a means to get to safety.

And a means to get to safety.

Narrator: the route to salvation Finally makes progress

Through the mountains.

But engineers realize there is a Fundamental flaw in their plan.

Predictably, Progress on the road was slow,

And that led The l.A. Authorities to say,

"Hang on, let's have a re-think.

What we're really doing Is creating a potential

For a huge traffic jam In the future.

Do we really want to do that?

It's gonna be world war iii just Trying to get to that road."

Dickrell: given los angeles's Notoriously congested highways,

Dickrell: given los angeles's Notoriously congested highways,

The premise that The armageddon highway

Would have been able To safely transport

The denizens Of los angeles to safety

Is basically ludicrous,

Especially when viewed From a modern perspective

Of grid-locked Los angeles highways.

Narrator: and with the advent Of faster intercontinental

Ballistic missiles Giving even less warning,

Escape from soviet nuclear Fallout becomes impossible.

L.A.'s evacuation plans Through shoemaker canyon

L.A.'s evacuation plans Through shoemaker canyon

Are now useless.

When you really think about it, That given the warning time,

Which is next to nil,

It's basically impossible To evacuate major urban areas.

Now, I think by the late 1960s They're thinking,

"Well, this is just A whopping waste of money.

It's just not worth it."

Narrator: In 1969, 13 years after The project commences,

The los angeles authorities Finally call time

The los angeles authorities Finally call time

On the escape route.

All that has been achieved Of the 25-mile shortcut

Through shoemaker canyon Is a 4 1/2 mile road

And two tunnels That lead to nowhere.

Today, the road and tunnel Still stand on the slopes

Of shoemaker canyon But are rarely visited.

They survive as a monument To cold war paranoia,

And the real dangers Felt by the citizens of l.A.

Half a century ago.

Half a century ago.

Today, the most striking remains Of the road are its tunnels.

And it makes you appreciate The fact that this is

What cold war paranoia Forced us to do.

*

Narrator: over 6,000 across The atlantic in northern italy,

In the mountainous province Of belluno

Is an engineering wonder.

*

Towering above The town of longarone,

Towering above The town of longarone,

An 871-foot wall Of concrete spans

The tree-covered cliffs On either side.

*

All of a sudden, You'd come to an opening

With this big concrete wall In front of you.

*

It's an astonishingly impressive Piece of engineering.

Even by modern standards,

It's still one Of the highest in the world.

*

*

Narrator: 627-feet wide at its summit,

The structure narrows To just 89 feet at its base,

Which is an incredible 72-feet thick.

Constructed using 1.3 billion Cubic feet of concrete,

This fortress holds back Over 9 billion cubic feet

Of sedimentary rock and debris.

Standing at its base, Gazing up at it,

You would be overwhelmed At its size.

You would be overwhelmed At its size.

You would be dwarfed.

Buy why did engineers Build such a giant structure

In such a difficult place?

And why was it abandoned?

*

As post-war italy rises From the ashes,

A drive to boost Its faltering economy

Comes in the form Of rapid industrialization,

Which demands A huge amount of power.

In the 1950s when italy Was just coming off

The back of The second world war,

The back of The second world war,

Its economy was in A state of devastation.

Narrator: so, drawing on Its natural resources,

The country harnesses masses Of water in the italian alps,

Supplied by the rivers, Snowmelt, and high rainfall.

It's perfect For hydroelectricity.

*

Jerram: hydroelectric power Is incredibly attractive

In a mountainous region,

Because if you can Have a tight valley,

And you can trap water high up,

You've suddenly got the ability For that water to move downhill

You've suddenly got the ability For that water to move downhill

Very quickly And generate free electricity.

Narrator: in the shadow Of the mighty monte toc,

Engineers identify the deep And narrow vajont valley

As the ideal location To store huge amounts of water

And use it as part Of a vast hydroelectric plant.

Jerram: the gorge itself was A particularly attractive site

Because of the sheer Highness of the gorge,

And the amount Of the volume of water

That you'll be able to get

For such a small cutting off Of the valley.

For such a small cutting off Of the valley.

You can more or less Throw a stone

From one side to the other.

Narrator: to kick-start Italy's post-war economy,

The engineers devise this --

The vajont dam.

*

Dickrell: A curved dam is a very classical Way of structuring a dam,

To make it strong and resist

The fluid forces Of the reservoir behind it.

Narrator: it's designed to hold A three-mile-long reservoir.

Narrator: it's designed to hold A three-mile-long reservoir.

When you have a huge of water Pushing up against a dam,

And the dam is in The shape of an arch,

And it's made from materials

That are really good In compression,

Then what it means is that The arch is really strong,

You don't need as much material To resist that massive force,

And it stays stable.

And the clever thing is that It channels all of that force

Into the cliff faces, Either side of it.

Narrator: Employing over 400 laborers From the local area,

Narrator: Employing over 400 laborers From the local area,

Work starts in 1957 On this powerful structure.

The vajont dam Is the centerpiece

Of a hydroelectric network In the area.

Engineers hope it will hold over 6 billion cubic feet of water

And feed 4 power stations via 37 Miles of water-delivery tunnels,

Bringing much needed energy To the cities of northern italy.

For three years, workers labor

Until dam's Distinctive curvature

Is finally in place.

Is finally in place.

Something that big, something So impressive in the landscape

To be built at that time, Is a real engineering feat.

Narrator: The filling of the reservoir Basin begins in february 1960.

But will it work?

Jerram: when you're filling The dam up with water,

There's a lot of weight, A lot of pressure

That's being exerted On the sides of the valleys.

But at the same time, You're bringing water into areas

Where it's not normally there All of the time.

Where it's not normally there All of the time.

So, those two factors Clearly changed the way

The landscape was reacting.

Narrator: for nine months,

The dam hold its water level At over 590 feet,

Producing 9,000 kilowatts Of energy

For just One power station alone.

But a 6,000-foot crack

Soon appears across The slope of monte toc,

And on november 4th, 1960, A massive landslide happens.

*

*

Over 24 million cubic feet Of rock breaks off

And slides into the reservoir

Just under 2,000 feet From the dam wall,

Drastically increasing The water level,

Which could breach The crest of the dam.

Providing you keep enough space In the level of the reservoir,

And this slow rock mass Moves into it,

It would not necessarily Be a problem.

They can control it.

Narrator: the engineers Lower the water level,

Easing the pressure On the surrounding cliffs,

Easing the pressure On the surrounding cliffs,

Which stop the landslide.

To control further land movement

While also keeping The dam running,

They raise and lower The reservoir level accordingly,

Causing fatigue in the process.

So, if you imagine Taking a metal spoon,

And then you bend it back And forth a number of times,

Eventually that spoon Is gonna snap.

So, by raising and lowering The level of the water

In the reservoir,

They changed the pressure Exerted on the soil.

They changed the pressure Exerted on the soil.

Narrator: Using the water level in the dam

To control the surrounding Landmass is risky.

It makes it virtually impossible To predict

How fast any landslide Might react.

Will this technique Stop future landslides?

And why was the vajont dam Abandoned?

*

*

Narrator: in northern italy, High in the alps,

Is one of the tallest concrete Barriers in the world --

The vajont dam.

In 1960, engineers lower and Raise the water in the reservoir

To ease the pressure On the surrounding cliffs

In order to save the dam And stop future landslides.

The technique works.

For three more years,

For three more years,

The dam successfully supplies Water to four power stations,

Producing much needed Hydroelectricity

To fuel the economy Of northern italy.

And in april 1963, with The landslides under control,

The engineers fill The reservoir behind the dam

To its capacity at 2,345 feet Above sea level.

The lesson that civil engineers Are reminded of time and again

Is to be acutely aware Of the natural surroundings

Is to be acutely aware Of the natural surroundings

And the geology in which You are building your stricture,

Because if you don't take heed Of those lessons,

The price you pay Could be devastating.

Narrator: then, at 10:39 p.M., October 9th, 1963,

Disaster strikes.

Over 9 billion cubic feet of Rock breaks away from monte toc,

Hurdling down At 68 miles an hour.

Hurdling down At 68 miles an hour.

The destructive debris smashes Into the reservoir below.

*

Bell: It wasn't just the massive earth

That slid away Into the reservoir.

It was the ferocious speed At which it came...

*

...45 seconds for effectively Half of the mountainside

To drop into the water.

To drop into the water.

*

Jerram: It cascades into the water And causes big waves.

Now, if you imagine a bath,

You've got a wall On one side of the bath,

And you've got a lip At the other side.

You jump into that bath,

You're gonna cause waves In two directions.

One will hit the wall And bounce back,

And that's exactly what happened In part of the valley.

The other's gonna actually Go over the rim.

It's literally Like an airborne tsunami.

Narrator: over 800 million Cubic feet of water

Becomes an 820-foot-high wave,

Becomes an 820-foot-high wave,

With the village of longarone In its path.

*

A massive amount of water forced Down such a tight gorge --

It displaced all of that air,

And it was almost like A shock wave of air,

Hit the village directly Before the water did,

And started destroying Some of the buildings,

And the next minute, A wall of water hits you.

It's got rocks in it, It's got trees in it.

It is like liquid sandpaper, and It just wipes the village clean.

It is like liquid sandpaper, and It just wipes the village clean.

Narrator: barely four minutes After the landslide begins,

Most of the town is obliterated By the subsequent wall of water.

It is one of the worst natural Disasters in european history,

Killing nearly 2,000 people.

The tragic irony Of this story is that

Whilst the villages below the Dam were completely destroyed

By the on-rush of water,

The dam itself remained Completely intact.

*

*

I guess that's A testament, really,

To the quality of the design And build of the dam,

Was just a dam built In the wrong place.

Narrator: the reservoir is Ultimately filled with debris,

And this spells the end For the great vajont dam.

It is abandoned.

Today, the vajont dam stands Isolated in the rocky landscape,

Scattered with hints Of its tragic past.

It forms a permanent reminder

It forms a permanent reminder

Of humanity's underestimation Of the forces of nature.

From an engineering perspective,

The vajont dam Should have become

One of the most impressive Dams in history.

Instead it's become One of the most infamous.

Jerram: It's an unfortunate tragedy, But from tragedy

We learn about How the landscape can react,

And hopefully we can mitigate

Against such tragedies In the future.

*

*

Narrator: Over 500 miles across europe,

South of dover On the british coast

Is the quiet seaside village Of littlestone

That has a secret past.

*

In the rough seas Of the english channel,

A mysterious 200-foot-long And 32-foot-wide steel structure

Lies partially submerged In its waters.

If you're one of the thousands Of holiday makers

Playing on the beach At littlestone

Playing on the beach At littlestone

Or even out For an early morning walk,

You'd quite happily dismiss it

As part of a sunken barge Or something.

But the fact is it's got far More historical significance

Than you could ever imagine.

Narrator: when the tide lowers To seven feet,

It reveals Some of its secrets --

A large block of concrete Nearly one-foot thick,

Weighing over 6,000 tons.

This bizarre object's Humble appearance

This bizarre object's Humble appearance

Disguises its Ambitious engineering.

Imagine that The engineers at the time

Were a little bit worried

That this was gonna be A big risk to take.

*

Narrator: But what is this strange object? Why is it here?

And why was it abandoned?

*

Narrator: in 1943, the largest Sea-borne invasion

Of the 20th century Is conceived -- d day,

Which calls for thousands Of allied troops and supplies

To invade nazi-occupied France in normandy.

But with the germans Heavily defending

Its major ports and harbors,

Where and how can the allies Land an entire invading army?

It becomes obvious to The british, to the americans,

It becomes obvious to The british, to the americans,

That it's immensely difficult To give an army

The supplies it needs To keep on fighting

Once you've thrown them Onto a beach.

Narrator: So, the allies developed A unique and ambitious plan

To supply the allied forces.

We, the allies, Brought together technology

From the field Of civil engineering,

Military engineering, Material science,

To create something That had not existed before --

To create something That had not existed before --

An entire harbor that can move 60 miles to where it's needed.

*

Code named "Operation mulberry,"

These floating harbors Can only succeed

If they have a particular Critical component --

The phoenix caisson.

The phoenix caisson Is but a tiny element

Of an incredibly complex,

But at the same time Brilliantly simple plan

To take a self-assembling, Floating harbor

To take a self-assembling, Floating harbor

Over to the beaches of normandy For the d day landings.

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Narrator: This watertight structure Is designed to provide

Much needed protection for The floating mulberry harbors

Of the invading allied forces.

But with wartime Steel shortages,

Engineers must turn to a more Readily available material,

Concrete, which, Amazingly, can float.

The idea of using Floating concrete blocks

Was actually nothing new.

Concrete vessels have been made Since the late 1800s.

Concrete vessels have been made Since the late 1800s.

What was different was using Them to create your own harbor

The size of any modern International ferry port.

Narrator: each concrete block Is five-stories high.

Intended to join together In a chain,

They serve As the protective walls

To the floating Mulberry harbors.

Bell: the purpose of The phoenix caissons

Was to act As a breakwater

As the outer limits Of the harbor

As the outer limits Of the harbor

Within which you'd have Much calmer waters

To land the supplies, The vehicles,

And the troops required On the beaches of normandy

For the d day landings.

Narrator: the caisson is made up Of reinforced concrete,

But it's the nine Hallow compartments

That hold The secret to its buoyancy.

Its volume consists Of a shell of concrete

Combined with an element Lighter than water -- air.

Weighing less than the water It displaces,

This concrete block Is able to float.

This concrete block Is able to float.

Equipped with sea valves Through which each compartment

Can be flooded,

These mobile blocks can be sunk

Wherever they are needed To become immovable.

The phoenix caisson itself Rates quite high in terms

Of the engineering ingenuity Involved in world war ii, right?

The engineers knew They had a job to do,

And they solved it Very efficiently

And very beautifully.

Narrator: construction begins In late 1943.

Workers must make 212 caissons With only six months

Workers must make 212 caissons With only six months

To complete this colossal task.

At 12 different coastal Locations around britain,

45,000 laborers Work in complete secrecy

To construct the caissons That require

Over 8 million cubic feet Of concrete

And 31,000 tons of steel.

A lot of the people would be Out there fighting the wars

And so on, so you'd get The unskilled laborer,

And then you can actually Train them up quite quickly

And then you can actually Train them up quite quickly

To fix steel, To pour the concrete,

'cause actually The process of doing that

Is not terribly technical Or complicated.

Narrator: to keep a project Of this magnitude under wraps,

The engineers used the caissons' Design and function

In a daring way.

To keep the plans For the d day landings

A complete secret From the germans,

Once the phoenix caissons Had arrived

At their assembly point On the south coast,

They were sunk to keep them out Of view below the water level,

They were sunk to keep them out Of view below the water level,

The idea being then that You could pump the water out

To float them up before Being towed over to france.

Narrator: in a mere six months, 212 phoenix caissons are built

And many are sunk In the english channel

In preparation for d day.

Now, true to their name, They must rise again

To play their part In the invasion of normandy.

Of course There's always the chance

That once you've done The first sink,

It actually does What it's supposed to do

And sticks into the ground

And then stays there Nice and stable

And then stays there Nice and stable

Against the sea currents.

Narrator: will engineers get All the caissons to re-float?

How will they work During the invasion?

And why was The phoenix caisson abandoned?

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Narrator: off the british coast, Lies the unsung hero of d day --

The phoenix caisson.

On june 7th, 1944, Within 24 hours

Of the allied invasion Of nazi-occupied france,

The troops need Supplies and fast.

This is the moment For the phoenix caisson to rise.

The majority of The giant concrete breakwaters

Hidden under the english channel Are successfully re-floated.

Hidden under the english channel Are successfully re-floated.

The allies sail them To the normandy beaches

To play their part In the invasion.

The phoenix caissons Had a crew of six men.

I mean, imagine that -- Being a crewman on board

A floating piece of concrete.

As they were towed Along by tugboats,

On board was A little accommodation hut,

A life raft in case Anything went wrong,

But they also had Anti-aircraft guns

Just in case They came under attack.

Just in case They came under attack.

At a rate of three knots, It takes 30 hours

To float 146 of these giant, Concrete caissons

To the secured beachheads Of omaha and gold.

Once sunk in place, they act As a two-mile-long breakwater

And outer wall of the harbor,

Fulfilling their crucial role In operation mulberry.

Concrete boxes Of the phoenix caisson,

In and of themselves Are not terribly impressive

When described As a concrete box.

When described As a concrete box.

But the usage of that caisson In landing material, men,

And equipment On the beaches of france

Was tremendously important.

Narrator: The mulberry harbor makes up An area of 500 acres

That is protected By a ring of phoenix caissons.

Critically, they calm the waters

So boats can safely dock At the floating piers,

Whether at high or low tide.

Having taken The germans by surprise,

The phoenix caissons Evade serious bombardment.

The phoenix caissons Evade serious bombardment.

Designed to last only 90 days, The mulberry harbors in france

Are still going strong 10 months later.

With the help Of the phoenix caissons,

The allies are able to unload 2.5 million men,

Half a million vehicles,

And four million tons Of goods and supplies.

Bell: to the engineers involved,

The mulberry harbors Were a phenomenal success.

D day landings Have been described

As one of the most monumental Events in modern history.

As one of the most monumental Events in modern history.

The phoenix caissons Were a huge part of that.

Narrator: But not all the caissons Are successful.

Many don't make it, and Off the coast of littlestone,

No matter how hard The engineers and pumps work

On the stranded caisson Beached there,

It refuses To rise to the surface.

Only problem was In certain areas

The seabed was extremely sticky, And try as they might,

The phoenix caisson At littlestone

Just couldn't be floated again.

Just couldn't be floated again.

Narrator: Unable to rise from its watery Grave of the shore of england,

It lies abandoned.

The phoenix caissons Played a crucial role

In the allies Winning world war ii

And are now a monument To military ingenuity

And inspiration for generations Of civil engineers to come.

The story of the Phoenix caisson at littlestone,

In a way, is a story of failure.

It never made Its way over to france.

But if you were able to get it Off the seabed today

But if you were able to get it Off the seabed today

And float it, It would still be able

To do the job It was designed to do,

And that's testimony

To quality engineering And a sound plan.

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