Abandoned Engineering (2016–…): Season 2, Episode 3 - The Italian Dam Disaster - full transcript

The Vajont Dam was completed in 1959 on the Vajont River, in the municipality of Erto and Casso. On 9 October 1963, during initial filling, a landslide caused a mega tsunami in the lake and 50 million cubic metres of water overtop...

A colossal wall of
concrete, perilously wedged

between mountains...

Something so impressive
in the landscape to be built

is a real engineering feat.

..Five epic circular structures

mysteriously deserted.

Everything is curved.

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

An American escape route
from nuclear armageddon.

You can almost envision
terrorised people trying to avoid

a nuclear explosion in a
large metropolitan area.



And an unsung
hero of world war ii.

The fact is it's got far
more historical significance

than you could ever imagine.

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?

In northern Italy,

in the mountainous
province of belluno,

just 60 miles from venice is a
monumental feat of engineering.

Towering above the
town of longarone,



an 870 foot wall of concrete
spans the tree-covered cliffs

on either side of
this narrow gorge.

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.

627 feet wide at its summit,

the structure narrows
to just 89 feet at its base.

Here the wall is an
immense 72 feet thick.

Constructed using 1.3
billion cubic feet of concrete,

this fortress is not
holding back water...

But rather 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 dwarfed.

But why did engineers
build this giant structure

in such a precarious location?

And why was it then abandoned?

Italy, at the end
of world war ii,

was a nation in tatters,

living under the
occupation of foreign armies.

The industrial heartland
in the northeast was vital

to the recovery of
its flagging economy.

But the region's factories
were chronically short of power.

In the 1950s, when
Italy was just coming

off the back of the
second world war,

its economy was in
a state of devastation.

Rising from the ashes,
the nation embarked

on a massive program
of industrialisation

backed by the us who saw Italy

as a valuable bulwark against
the threat of communism

from the east.

The program was
driven by hydroelectricity,

drawing on natural resources,
they harnessed the power of water

flowing from the Italian alps.

An abundance of
rivers, melting snow,

and high rainfall provided
perfect conditions.

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

very quickly and
generate free electricity.

In the shadow of
the mighty mount toc,

engineers identified the
deep and narrow vajont valley

as an ideal location
to store water...

Huge amounts of water

that could be used as part
of a vast hydroelectric plan.

The gorge itself was a
particularly attractive site

because of the sheer
height-ness of the gorge

and the amount of the volume
of water that you'd be able

to get for such a small
cutting off of the valley.

You can more or less throw a
stone from one side to the other.

At the core of this
hydroelectric network

was this...

The vajont dam!

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.

It was designed to hold
a 3-mile long reservoir.

When you have a huge amount
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.

Employing over 400
labourers from the local area,

work started in 1957.

The dam was the centrepiece of
an ambitious hydroelectric network

that spanned the region.

Engineers hoped it would 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 laboured

until the dam's
distinctive curvature

was finally in place.

For something that big,
something so impressive

in the landscape to be built

at that time is a
real engineering feat.

The filling of the reservoir basin
was underway in February 1960.

The moment of truth had arrived.

When you're filling
the dam up with water,

there's a lot of weight,
a lot of pressure

that's being exerted
on 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.

So, those two factors
clearly changed the way

the landscape was reacting.

For nine months, the
dam held its water level

at almost 600 feet,

part of a hydroelectric industry

that provided around
85% of the countries power.

However, a 6,000-foot crack

soon appeared across
the slope of mount toc.

And it was followed on 4 November,
1960, by a massive landslide.

24 million cubic feet of
rock slid into the reservoir

just under 2,000 feet
from the dam wall.

The water level
drastically increased

and it's threatened to
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.

Engineers lowered
the water level,

easing pressure on
the surrounding cliffs

and decided to employ a
fundamental principal of physics

to control any further
land movement.

So, if you imagine
taking a metal spoon

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

eventually that
spoon is going to snap.

So, by raising and lowering
the level of the water

in the reservoir, they
changed the pressure

exerted on the soil.

Using the water level in a dam to
control the surrounding land mass

is a risky operation.

It makes it virtually
impossible to predict

how fast the
landslide might react.

But for three years, the
technique appeared to pay off.

The dam successfully supplied
water to four power stations,

producing much needed
hydroelectricity for the cities

of northern Italy.

In April, 1963, with
the landslide seemingly

under control, engineers
filled the reservoir

behind the dam to 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

and the geology in which
you are building your structure

because, if you don't
take heed of those lessons,

the price you pay
could be devastating.

Disaster soon struck.

At 10:39pm on 9 October, 1963,

over 9 billion cubic feet

of rock broke away
from mount toc.

Hurtling down at 68 miles an
hour, the destructive debris smashed

into the reservoir below.

It wasn't just the mass
of 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.

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 the other side,

you jump into that bath,

you're gonna cause
waves in two directions.

One will hit the wall
and bounce back,

that's exactly what happened
in one part of the valley.

The other's going to
actually go over the rim.

It is literally like an
airborne Tsunami.

Over 800 million
cubic feet of water

became a massive wave,

a wave 820 feet high with
the village of longarone

directly 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 shockwave of air

hit the village directly
before the water did

and started destroying
some of the buildings.

And then 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.

Barely four minutes
after the landslide began,

most of the town was obliterated
by the subsequent wall of water.

It's one of the worst natural
disasters in European history.

Nearly 2,000
people lost their lives.

The tragic irony of this story

is that whilst the
villages below the dam

were completely destroyed
by the onrush of water,

the dam itself remained
completely intact.

I guess that's testament
really to the quality of the design

and build of the dam.

It was just a dam
built in the wrong place.

Ultimately, the reservoir
was filled with debris

and this spelt the end
for the great vajont dam.

It was then abandoned.

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

scattered with hints
of its tragic past.

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.

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.

Nearly 5,500 miles
away on the Cuban island,

Isla de la juventud
or isle of youth

sprawls a group of
peculiar structures.

Laid out like five spots on
a die, these circular giants

are a 174 feet in diameter

and tower over a 4 million
square foot open plane.

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.

What is it?"

The four outer buildings,
each 98 feet high,

consists 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 the local residents
and the conditions inside

were just atrocious.

The most bizarre feature
is a short lighthouse

like tower standing in
the centre 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.

What happened in these
strange hollowed out structures

on this remote island?

And why was this site abandoned?

In the 1920s, Cuba
was experiencing

a period of economic development

set against a backdrop
of political corruption.

Cuban president Gerardo machado

had ordered a major
construction program

to modernise the nation.

He was also determined to
stay in power at all costs...

And maintain ultimate control
over his political opponents,

not only physically
but psychologically.

To help him achieve
this, the dictator turned

to this extraordinary
island complex,

presidio modelo,
Cuba's model prison.

It was created and
conceived by a Cuban dictator

who drew upon an 18th century

social reformer whole ethos

was that behaviour could
be modified via surveillance.

The brainchild of
English philosopher

and prison reformer
Jeremy Bentham,

it was part of his
panopticon theory.

It was a design intended
to rehabilitate prisoners.

Surveillance was conducted
from an observation tower

at the centre of the structure.

And this was 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 neighbour downstairs

and so they have to be on
their best behaviour 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'.

Construction began in
1926 using inmate labour.

As each building was
completed, it was populated.

President machado's motive was
one of control rather than reform.

But as well as creating fear and
paranoia amongst the prisoners,

the structures also had
an engineering benefit.

This philosophy of
prisoner observation

actually lead to a very
interesting structural advantage,

and this advantage is the
fact that having a circular wall

going all the way round

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.

By the 1930s, presidio
modelo was fully operational,

with each building
containing 465 cells,

the complex was designed to
house less than 3,000 inmates.

Every cell faced inwards,

pointing towards the
central guard tower

and most incredibly,
there were no cell doors.

The architecture itself
was designed to control

the behaviour of
those imprisoned.

Gualdemar llevaron
was a guard here

and kept watch
over the prisoners.

(Speaks foreign language)

Unseen by the captives

who never knew if and
when they were being watch,

guards entered the observation
tower through a 98 foot long

underground tunnel.

Hidden from view, the
guards could keep an eye

on the prisoners
through narrow slits

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
was only a few feet from yours.

There's no privacy whatsoever.

And it must have generated
a whole lot of paranoia.

The large open space

within each building
made surveillance easy

and the result was the
inmates increasingly

policed themselves.

Even at meal times,
within the central dining hall,

there was no respite
from the constant silence

or watchful gaze 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.

Ironically, its cutting edge
design originally conceived

to rehabilitate convicts
earned the prison a reputation

for horror

and the prison relied on
more than watchful guards

to keep 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.

(Speaks foreign language)

President machado was
unable to hold on to power.

But the prison
continued for 27 years

and saw multiple regime changes.

But then in 1953, its
most notorious inmate

entered its doors.

The communist revolutionary
fidel Castro served two years here

for attempting to overthrow

the ruthless dictator
fulgencio Batista.

By his side was
his brother, Raul.

Though themselves treated
humanely as political prisoners,

fidel Castro witnessed firsthand
the psychological success

of the jail's design and
realised the potential

for control and paranoia.

It was knowledge and
experience he went on to exploit

when he overthrew Batista in
1959 to become leader of Cuba.

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

destroy the place, he
doesn't knock it down.

No!

He then sends his
political opponents there.

I think that's quite rich.

For eight years, Castro
used presidio modelo

to Bury his enemies.

But these political prisoners
posed serious threats to security.

One dramatic plan hatched
during the CIA-backed

bay of pigs invasion in 1961
involved destroying 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.

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.

Dynamite couldn't destroy
presidio modelo but Castro could.

The prison had a
capacity for 3,000 inmates,

but he packed it with
double that number.

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.

This measure of
overpopulation backfired.

Cramped, dirty, and overcrowded,
it encouraged growing resistance

from the inmates
and was increasingly

seen by Castro
as a security risk.

Cuba's model prison
closed its doors in 1967

and Castro's enemies were
dispersed to other prisons.

It just stops to function.

And it's a little bit
dilapidated anyways,

but the political
climate had changed

and it no longer had
a purpose to serve.

The unique design and
function of the prison

made the buildings virtually
impossible to re-purpose.

After 41 years of oppression and
paranoia, they were abandoned.

The gigantic circular cell
blocks of presidio modelo

are now decaying shells
and stark reminders

of Cuba's political turmoil.

While Raul Castro,
in early 2018,

remains president of Cuba,

the hospital building honours
its most famous inmate,

his brother, fidel.

But these structures
also represent the closest

anyone has come to
turning Jeremy Bentham's

panopticon concept
into a reality.

Today, the prison is a museum.

It's a school.

It's a research centre.

And that's about right.

Because what it really was,
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.

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 for?

And where does it lead?

When you first see these
entrances opening up

on the sides of the
mountain, you can't fathom

why the effort was gone to to
build these huge 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.

A tiny light at the end of
the dark tunnel suggests

this structure runs directly
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.

Why did someone go
to the trouble of building

this immense tunnel only
to seemingly down tools

and walk away?

Why was it abandoned?

In the 1950s, the
cold war loomed large

over a paranoid america.

The nation feared
not only an invasion

but nuclear attack
from the Soviet union.

La's many aerospace facilities

and military bases made
the city a prime target.

America's early warning
systems could recognise potential

threats hours before impact.

But in that small window of
time, how would the authorities

save the then population
of nearly 2 million people?

The la 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.

(Siren blares)

Man: In this troubled
stage of the atomic age,

our very lives may depend
on always being alert.

If the Soviets launched a
nuclear strike on Los Angeles,

a credible escape plan
would need to be set 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 tunnelling right on through.

So, a 25-mile
shortcut was devised.

Designed to speed
the city's residents

through the San Gabriel mountains
via multiple tunnels to the safety

of the mojave desert...

This path to safety

was shoemaker canyon road,

better known as
armageddon highway.

The armageddon highway
would work in premise

that the entire
population of Los Angeles

would get in their cars

and exit away from the city

and the eventual
destruction that would happen.

This was part of the
culture at the time,

this fear that the other
guy has the technology

and can strike us and
that we need to have

some kind of way
to protect ourselves.

Once complete, these tunnels
were designed to form a costly

but potentially vital evacuation
route high above the city.

Given the cold war in the 1950s,

everyone was afraid of
nuclear war and in that,

the response of the
government was to drill a hole

through 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.

(Loud explosion)

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 the winter,

and the continuous
threat of landslides,

the challenge was
all the more extreme.

Construction started in 1956.

To hold up in this
harsh environment,

interlocking steel beams
and moulded concrete

were needed to shore
up critical stress points

of the 1,000 foot long tunnel.

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 a road.

Not only was their
heart probably not into it,

but they didn't
have the skill sets.

With unskilled workers
struggling to cut through solid rock,

the two-Lane escape highway
made agonisingly slow progress.

It was only completed in
1961, a full five years later.

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
us city a means of escape

and a means to get to safety.

To be inside of it, you
can almost envision

terrorised people trying to
avoid a nuclear explosion

in a large metropolitan area.

The route to salvation
had finally made progress

cutting through the mountains,
but engineers realised

there was a fundamental
flaw with their plan.

Predictably, progress
on the road was slow

and that led to la
authorities to say, "hang on.

Let's have a rethink."

"What we're really doing
is creating a potential

very huge traffic
jam in the future.

Do we really wanna do that?

It's going to be world war III
just trying to get to that road."

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 gridlocked Los
Angeles highways.

And with the advent of faster
intercontinental ballistic missiles

giving even less warning,

escape from the Soviet nuclear
fallout became impossible.

La's evacuation plans
through shoemaker canyon

were 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,

"whoa, this is just a
whopping "waste of money.

It's just not worth it."

In 1969, 13 years after
the project commenced,

the Los Angeles authorities finally
called time on the escape route.

All that had been achieved
of the 25 mile shortcut

through shoemaker
canyon was a 4.5 mile road

and two tunnels
that led to nowhere.

Today, the road and tunnels
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
la 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.

Thousands of miles
across the Atlantic ocean,

on the south coast of
england is the seaside village

of littlestone.

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 holidaymakers

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.

The fact is it's got far
more historical significance

than you could ever imagine.

At low tide,

a large 6,000 tonne block
of concrete is revealed.

Yet the object's humble
appearance belies

its engineering and
historic importance.

I can imagine that the
engineers at the time

were a little bit worried
that this was gonna be

a big risk to take.

But how did this
simple-looking structure

play a key role

in one of the largest
invasions in history?

Why is it here?

And why was it abandoned?

In 1944, a force of unprecedented
scale was being mobilised

across southern england.

Millions of soldiers backed up
by 12,000 aircraft and an armada

of 7,000 ships, all
preparing for d day.

It was a phenomenal
logistical undertaking.

And while the coastline was
heavily defended by German forces,

the challenge was not simply
landing this massive invasion force.

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.

The allies developed a unique
and ambitious plan to ensure

they could maintain
the flow of supplies.

We, the allies, brought
together technology

from the field of civil
engineering, military engineer,

materials science
to create something

that had not existed
before, an entire harbour

that can 60 miles
to where it's needed.

Codenamed operation mulberry,
a critical element of these giant

floating harbours was
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 harbour over to
the beaches of normandy

for the d day landings.

These watertight structures
were designed to provide

valuable protection
for the artificial ports.

(Gun fires)

But with wartime
steel shortages,

engineers turned to a more
readily available material.

The idea of using
floating concrete blocks

was actually nothing new.

Concrete vessels have been
made since the late 1800s.

What was different was using
them to create your own harbour

the size of any modern
international ferry port.

Each concrete block
was five storeys high,

intended to join
together in a chain,

they would serve
as a protective barrier

to the floating
mulberry harbours.

The purpose of the
Phoenix caissons

was to act as a breakwater
as the outer limits of the harbour

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 landing.

The caisson is made of a
reinforced concrete shell,

but nine hollow compartments
ensure its buoyancy.

Equipped with sea
valves, each compartment

can be flooded again and
the block sunk into position.

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.

Construction began in late
1943, workers were tasked

with making 212 caissons
with only 6 months to complete

this colossal task.

At 12 different coastal
locations around britain,

45,000 labourers worked
in complete secrecy.

In total, this
endeavour required

over 8 million cubic
feet of concrete

and 31,000 tonnes of steel.

A lot of people would
be out there fighting

the wars and so on, so you
get the unskilled labour in

and 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.

While it was impossible
to fully conceal a project

of this magnitude from the
Germans, it was essential that Hitler

remain unsure of both when and
where the invasion would come.

To help keep these
preparations under wraps,

engineers used the caisson's
design and function to great effect.

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.

The idea being then that
you'd pump the water out

to float them up before
being towed over to France.

In a mere 6 months,
212 Phoenix caissons

were successfully
built and many sunk

in the English channel
in preparation for d day.

Now, true to their name,
they were to rise again

to play their part in
the invasion of France.

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 against the sea currents.

160,000 men crossed the
channel on 6 June, 1944.

Within 24 hours, the
beachheads were secured.

The allies now had
to land enough arms

and supplies to equip an
army that would liberate France

and ultimately Europe.

The Phoenix
caissons were refloated

and sailed across the
normandy beaches to create

the artificial ports that would
make this epic feat possible.

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 tug boats on board,

there 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.

At a rate of 3 knots, it
took 30 hours to float

146 of these giant concrete
caissons to the beachheads,

codenamed Omaha and gold.

Sunk into position, they functioned
as a 2 mile long breakwater

and outer wall of
the artificial ports,

fulfilling their crucial
role in operation mulberry.

The concrete boxes
of the Phoenix caisson,

in and of themselves,
are not terribly impressive

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.

The mulberry harbour
made up an area of 500 acres

that was protected by a
ring of Phoenix caissons.

Critically, they calmed
the waters so boats

could safely dock
at the floating piers

whether at high or low tide.

Having taken the
Germans by surprise,

the Phoenix caissons
evaded serious bombardment.

Designed to last only 90
days, the mulberry harbour

at gold beach was still
going strong 10 months later.

With the help of the
Phoenix caissons,

the allies were able to unload
a staggering 2.5 million men,

0.5 vehicles, and 4 million
tonnes of goods and supplies.

For the engineers involved,
the mulberry harbours

were a phenomenal success.

The d day landings
have been described

as one of the most monumental
events in modern history.

The Phoenix caissons
are a huge part of that.

Yet not all the caissons
were successful.

Many didn't make it.

No matter how
hard engineers tried,

the caisson beached here
off the coast of littlestone

refused to budge and
remained fully submerged.

The 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.

Unable to rise from
its watery grave off

the shore of england,
it still lies abandoned.

These simple-looking

concrete blocks
played a crucial role

in the allies successfully
retaking France

and winning world war ii.

They are a monument
to military ingenuity

and inspiration to future
generations of civil engineers.

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 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.

Now abandoned, they were once

on the cutting edge
of human engineering.

Within these decaying structures
are the echoes of history.

They speak of war and
terror but also of exploration

and human endeavour.

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