- 2 days ago
Category
📺
TVTranscript
00:02Five strange circular structures mysteriously deserted.
00:07Everything is curved. There's no place where you can go and not be seen.
00:12An abandoned wall of concrete perilously wedged between mountains.
00:18Something so impressive in the landscape to be built is a real engineering feat.
00:25And an American escape route from nuclear Armageddon.
00:30You could envision terrorized people trying to avoid a nuclear explosion in a large metropolitan area.
00:38Once, they were some of the most advanced structures and facilities on the planet.
00:43At the cutting edge of design and construction.
00:47Today, they stand abandoned, contaminated, and sometimes deadly.
00:54But who built them? And how? And why were they abandoned?
01:19On the Cuban island of Isla de la Juventud sprawls a group of peculiar structures.
01:25On the Cuban island of Isla de la Juventud sprawls a group of peculiar structures.
01:31Laid out like five spots on a die, these circular giants are 174 feet in diameter.
01:39And tower over a four million square feet open plain.
01:45If you were flying over the island and you looked down and saw these five yellow circular buildings.
01:52You would think, what, is this some sort of industrial beehive?
01:56Is it a power plant? No, it's not really shaped like a conventional power plant.
02:01What is it?
02:03The four outer buildings, each 98 feet high, consist of six levels, yet inside there are no floors.
02:12Only a colossal empty space.
02:15Light pierces the dank, grim interior through 465 rectangular openings.
02:23Had a pretty sinister reputation amongst the local residents.
02:28And the conditions inside were just atrocious.
02:32The most bizarre feature is a short, lighthouse-like tower standing in the centre of each building.
02:39When you walk inside, you're instantly struck by the fact that there are no straight corridors.
02:46Everything is curved.
02:47You are constantly in view from somewhere else.
02:51There's no place where you can go and not be seen.
02:54And that was all by design.
02:57What happened on this remote island in these odd structures?
03:01And why was this site abandoned?
03:07In the 1920s, Cuba experiences a period of economic development against a backdrop of political corruption.
03:16Cuban President, Gerardo Machado, is determined to stay in power at all costs.
03:22But to do this, he must maintain ultimate control over his political opponents.
03:28Not only physically, but also psychologically.
03:31The solution for this dictator's total domination is the incredible island complex Presidio Modelo, Cuba's model prison.
03:42It was created and conceived by a Cuban dictator who drew upon an 18th century social reformer,
03:52whose whole ethos was that behaviour could be modified via surveillance.
03:59Though originally intended as a tool to rehabilitate prisoners, surveillance here comes in the form of an oppressive observation tower
04:08at the centre of the structure,
04:10which is key to the building's design.
04:13You have a central observation tower, and then you have a circular structure that surrounds that tower, which is where
04:19all the cells are.
04:20And the idea is that all the prisoners in their cells are not really sure whether the guards are looking
04:26at them or looking at their neighbour downstairs,
04:28and so they have to be on their best behaviour all the time.
04:31That design inside the prison certainly feels quite menacing to me.
04:36That central tower with guards, who theoretically then can be observing what's going on in all of those prison cells
04:43at any time,
04:44it certainly feels quite big brother.
04:46Something you might have read in George Orwell's 1984.
04:50Construction begins in 1926 using inmate labour. As they complete each building, it is populated.
04:58And these structures are not just designed to create paranoia amongst the prisoners.
05:04They also have an unexpected engineering benefit.
05:07This philosophy of prisoner observation actually led to a very interesting structural advantage.
05:14And this advantage is the fact that having a circular wall going all the way round meant that there was
05:20an inherent stiffness in the structure.
05:22That meant you don't need to put intermediate floors in to keep the structure stable.
05:27By the 1930s, Presidio Modelo is fully operational.
05:32Each building contains 465 cells that house two inmates, all of which face inwards towards the central guard tower.
05:42It has a total capacity of over 3,000 inmates.
05:46But most incredibly, there are no cell doors.
05:50The architecture itself affects, shapes and enforces the behaviour of those imprisoned.
05:58The tower was to control the prisoners inside.
06:01If there were any discussions, we'd say,
06:04Hey there!
06:05Shh!
06:06Watch it!
06:07And they would.
06:09The tower was to maintain order.
06:13Unseen by the prisoners, who never know if and when they are being watched,
06:18the guards enter the observation tower through a 98 feet long underground tunnel.
06:24Hidden from view, the guards keep an eye on the prisoners through narrow slits in the top of the tower.
06:30You're constantly being watched, not only by the prison guards from the central tower, but other prisoners whose cell is
06:37only a few feet from yours.
06:39There's no privacy whatsoever, and it must have generated a whole lot of paranoia.
06:45The large open space within each building makes surveillance easy, and the result is that the inmates increasingly police themselves.
06:55Even at mealtimes, within the shorter central structure, there is no respite from the watchful eye of the guards.
07:03You would think that leaving your cell where you're constantly under surveillance and going for a meal would be a
07:09nice experience of chatting with your fellow cellmates.
07:12Not at all.
07:13You went to a building that was called the Hall of the 3000 Silences, and it was aptly named because
07:21you weren't allowed to speak.
07:22Imagine how oppressive that would be. You're being watched all day in your cell, and now you're having a meal,
07:28and you can't even speak.
07:33Ironically, its cutting-edge design, originally conceived to rehabilitate convicts, earns Presidio Modelo a reputation for horror.
07:42And the prison relies on more than watchful guards to keep its inmates under control.
07:49There are all sorts of legends about the prison, including the fact that there were crocodiles in the ponds and
07:55lakes on the perimeter of the prison itself.
07:58When this was built, there were crocodiles living there.
08:01And the prisoner who escaped, if he didn't get caught running, he would be taken by them when he got
08:08there.
08:08No freedom. That was it.
08:13But will the architecture of paranoia at Presidio Modelo be enough to keep the prisoners in line and maintain a
08:20dictatorial grip on power?
08:23And why was the prison abandoned?
08:37Off the Cuban coast, on Isla de la Juventu, sprawls Cuba's abandoned model prison, Presidio Modelo.
08:46After multiple regime changes, its terrifying approach to imprisonment works for 27 years.
08:53But then, in 1953, its most notorious inmate enters its doors.
09:00The communist revolutionary Fidel Castro serves two years here for attempting to overthrow the ruthless dictator Fugencio Batista.
09:10Seeing the psychological success of the jail's effective design firsthand,
09:16Castro realizes the potential power of paranoia when he overthrows Batista in 1959 to become president of Cuba.
09:27When he comes into power, he doesn't, you know, destroy the place.
09:31He doesn't knock it down.
09:32No, he sends his political opponents there.
09:35I think that's quite rich.
09:37For eight years, Castro uses Presidio Modelo to bury his enemies.
09:43But his political prisoners begin to put up resistance and pose serious security and political risks.
09:50There is a dramatic plan to get rid of the prison using the underground guard tunnels.
09:56There was actually a plan to blow up these structures using that tunnel by actually packing it in with explosives.
10:04And thinking about the sheer size and scale of these structures, the fact that they had this inherent stiffness because
10:11of its shape,
10:12I think it would have been quite difficult to actually bring that structure down.
10:17Dynamite may not be able to destroy Presidio Modelo, but Castro does.
10:23The prison has a capacity for 3,000 inmates, but he packs it with double that number.
10:30Something that was originally designed to house up to 3,000 prisoners was now housing anything from 6,000 to
10:358,000 prisoners.
10:38Riots were commonplace fights, unsanitary conditions, and the place was just hellish.
10:44The measure of overpopulation backfires, encouraging further resistance from the inmates, eventually leading to the prison's demise.
10:55Cramped, dirty, and overcrowded, Cuba's model prison is forced to close its doors for good in 1967,
11:03and Castro's enemies are dispersed to other prisons.
11:07It just stops to function, and it's a little bit dilapidated anyways, but the political climate had changed,
11:14and it no longer had a purpose to serve.
11:17The unique design and function of the prison makes the buildings virtually impossible to be repurposed.
11:24And after 41 years of oppression and paranoia, they are abandoned.
11:30Now, the gigantic circular cell blocks of the Presidio Modelo are decaying shells,
11:36and stark reminders of Cuba's political turmoil.
11:40As symbols, they demonstrate that groundbreaking architectural design can not only shape human behavior,
11:47but also reveal the limits of social reform and how easily it can backfire.
11:52Today, the prison is a museum. It's a school. It's a research center.
11:57And that's about right, because what it really was, historically,
12:01I think we look back at it as an innovative attempt at social reform.
12:05It was all about surveillance. And actually, it was quite ahead of its time.
12:16Over 2,000 miles away, across the Gulf of Mexico,
12:20a barren landscape hides an enigmatic enterprise of forgotten engineering.
12:28High above Los Angeles is a closed-off road winding 900 feet up in the San Gabriel Mountains.
12:34It leads to a mysterious masonry arch over 20 feet high, driven into its slopes.
12:40But what is this an entrance to?
12:42When you first see these entrances opening up on the sides of the mountain,
12:46you can't fathom why the effort was gone to, to build these huge, great, big tunnels.
12:53For me, you'd expect to see some kind of railway or a road or something coming out of it, but
12:56none of that's there.
12:57In fact, it becomes quite mysterious.
13:00The light at the end of the tunnel shows that this structure runs for 1,000 feet through the mountain.
13:07As you're standing there, you appreciate what an impressive feat of engineering it is,
13:13and how difficult it would have been to have made.
13:17The interesting thing is, there's a lot more to this story than meets the eye.
13:23Why did someone go to the trouble of building this immense structure through a mountain?
13:28And why was it abandoned?
13:32In the 1950s, the threat of the Cold War looms over a paranoid America.
13:37The nation fears not only an invasion, but nuclear attack from the Soviet Union.
13:44L.A.'s many aerospace facilities and military bases make the city a prime target.
13:52America's early warning systems can recognize potential threats hours before impact.
13:58But in that small window of time, how can the authorities save the then population of nearly 2 million?
14:06The L.A. authorities began to wonder, how would we evacuate?
14:11In the 1950s, there might have been 20 minutes or half an hour's warning of an impending nuclear attack on
14:19Los Angeles.
14:20Any evacuation for the people of Los Angeles had to be prepared in advance.
14:27In this troubled stage of the atomic age, our very lives may depend on always being alert.
14:35If the Soviets strike Los Angeles with nuclear weapons,
14:39a credible escape plan needs to be in place for its citizens.
14:43To get out of Los Angeles, you've got to get through the hills and the mountains and out the other
14:47side.
14:48That means either twisting and turning through canyons or tunneling right on through.
14:54So a 25-mile shortcut is devised that's designed to speed the city's residents through the San Gabriel Mountains via
15:03multiple tunnels to the safety of the Mojave Desert.
15:08This path to safety is Shoemaker Canyon Road, better known as the Armageddon Highway.
15:16The Armageddon Highway would work in premise that the entire population of Los Angeles would get in their cars and
15:22exit away from the city and the eventual destruction that was happening.
15:27This was part of the culture at the time, this fear that the other guy has the technology and can
15:35strike us and that we need to have some kind of way to protect ourselves.
15:42Will Shoemaker Canyon Road work as an escape route from nuclear fallout in Los Angeles?
15:49And why was it abandoned?
16:00In the 1950s, gripped by Cold War paranoia and desperation, Los Angeles authorities ordered the construction of Shoemaker Canyon Road
16:10with multiple tunnels driven through the solid rock of the San Gabriel Mountains.
16:16Once complete, they are designed to form a costly but potentially vital evacuation route high above the city.
16:24Given the Cold War 1950s, everyone was afraid of nuclear war and in that the response the government was to
16:32drill a hole through a mountain such that the population of Los Angeles could escape given all out nuclear war.
16:39One Soviet nuclear weapon air bursted over Los Angeles could kill more people than were killed in Hiroshima, Nagasaki combined.
16:54But carving a road through a mountain of hard rock is difficult at the best of times.
17:00And in the volatile region of the San Gabriel Mountains, with severe heat in the summer, avalanches in winter and
17:07the continuous threat of landslides, the challenges are all the more extreme.
17:11To hold up in this harsh environment, interlocking steel beams and moulded concrete are needed to shore up critical stress
17:20points of the thousand foot long tunnel as construction starts in 1956.
17:26You would have thought that a project of this importance would have warranted professionals.
17:32But what they got instead was a chain gang.
17:35I mean, they literally asked the inmates of nearby prisons to go up into the mountains, build the road.
17:42Not only was their heart probably not into it, but they didn't have the skill sets.
17:47With unskilled workers struggling to cut through solid rock, the two-lane escape highway makes agonizingly slow progress.
17:56This thousand feet tunnel takes five years and is only completed in 1961.
18:02To be inside of it, you can almost envision terrorized people trying to avoid a nuclear explosion in a large
18:09metropolitan area.
18:10The fact that they were prepared to blast their way through these mountains just shows that level of panic and
18:16urgency that was felt to give the people of a major US city a means of escape and a means
18:24to get to safety.
18:27The route to salvation finally makes progress through the mountains.
18:31But engineers realize there is a fundamental flaw in their plan.
18:36Predictably, progress on the road was slow, and that led the LA authorities to say, hang on, let's have a
18:42rethink.
18:42What we're really doing is creating a potential for a huge traffic jam in the future.
18:47Do we really want to do that?
18:49It's going to be World War III just trying to get to that road.
18:54Given Los Angeles' notoriously congested highways,
18:57the premise that the Armageddon Highway would have been able to safely transport the denizens of Los Angeles to safety
19:04is
19:05is basically ludicrous, especially when viewed from a modern perspective of gridlocked Los Angeles highways.
19:12And with the advent of faster intercontinental ballistic missiles giving even less warning,
19:18escape from Soviet nuclear fallout becomes impossible.
19:23LA's evacuation plans through Shoemaker Canyon are now useless.
19:28When you really think about it, that given the warning time, which is next to nil,
19:35it's basically impossible to evacuate major urban areas.
19:39Now, I think by the late 1960s, they're thinking,
19:43well, this is just a whopping waste of money. It's just not worth it.
19:50In 1969, thirteen years after the project commences,
19:55the Los Angeles authorities finally call time on the escape route.
19:59All that has been achieved of the 25-mile shortcut through Shoemaker Canyon
20:04is a four-and-a-half-mile road and two tunnels that lead to nowhere.
20:10Today, the road and tunnels still stand on the slopes of Shoemaker Canyon, but are rarely visited.
20:16They survive as a monument to Cold War paranoia and the real dangers felt by the citizens of LA half
20:23a century ago.
20:25Today, the most striking remains of the road are its tunnels.
20:30And it makes you appreciate the fact that this is what Cold War paranoia forced us to do.
20:41Over 6,000 miles across the Atlantic in northern Italy,
20:45in the mountainous province of Belluno is an engineering wonder.
20:55Towering above the town of Longorone,
20:58an 871-foot wall of concrete spans the tree-covered cliffs on either side.
21:06All of a sudden, you'd come to an opening with this big concrete wall in front of you.
21:14It's an astonishingly impressive piece of engineering.
21:20Even by modern standards, it's still one of the highest in the world.
21:28627 feet wide at its summit, the structure narrows to just 89 feet at its base, which is an incredible
21:3672 feet thick.
21:39Constructed using 1.3 billion cubic feet of concrete, this fortress holds back over 9 billion cubic feet of sedimentary
21:49rock and debris.
21:51Standing at its base, gazing up at it, you would be overwhelmed at its size, you would be dwarfed.
21:57But why did engineers build such a giant structure in such a difficult place?
22:02And why was it abandoned?
22:08As post-war Italy rises from the ashes, a drive to boost its faltering economy comes in the form of
22:15rapid industrialization,
22:17which demands a huge amount of power.
22:21In the 1950s, when Italy was just coming off the back of the Second World War, its economy was in
22:27a state of devastation.
22:29So, drawing on its natural resources, the country harnesses masses of water in the Italian Alps, supplied by the rivers,
22:38snowmelt and high rainfall.
22:40It's perfect for hydroelectricity.
22:45Hydroelectric power is incredibly attractive in a mountainous region because if you can have a tight valley and you can
22:52trap water high up,
22:53you've suddenly got the ability for that water to move downhill very quickly and generate free electricity.
23:01In the shadow of the mighty Mount Tok, engineers identified the deep and narrow Vyant Valley as the ideal location
23:08to store huge amounts of water and use it as part of a vast hydroelectric plan.
23:15The gorge itself was a particularly attractive site because of the sheer heightness of the gorge and the amount of
23:21the volume of water that you'd be able to get for such a small cutting off of the valley.
23:26You can more or less throw a stone from one side to the other.
23:30To kickstart Italy's post-war economy, the engineers devise this, the Vyant Dam.
23:42A curved dam is a very classical way of structuring a dam to make it strong and resist the fluid
23:49forces of the reservoir behind it.
23:51It's designed to hold a three-mile-long reservoir.
23:55When you have a huge amount of water pushing up against a dam and the dam is in the shape
24:02of an arch and it's made from materials that are really good in compression,
24:06then what it means is that the arch is really strong, you don't need as much material to resist that
24:12massive force and it stays stable.
24:14And the clever thing is that it channels all of that force into the cliff faces either side of it.
24:21Employing over 400 labourers from the local area, work starts in 1957 on this powerful structure.
24:29The Vyant Dam is the centrepiece of a hydroelectric network in the area.
24:34Engineers hope it will hold over 6 billion cubic feet of water and feed four power stations via 37 miles
24:43of water delivery tunnels,
24:45bringing much-needed energy to the cities of northern Italy.
24:48For three years, workers labour until the dam's distinctive curvature is finally in place.
24:56Something that big, something so impressive in the landscape to be built at that time, is a real engineering feat.
25:07The filling of the reservoir basin begins in February 1960.
25:12But will it work?
25:15When you're filling the dam up with water, there's a lot of weight, a lot of pressure that's being exerted
25:20on the sides of the valleys.
25:22But at the same time, you're bringing water into areas where it's not normally there all of the time.
25:27So those two factors clearly changed the way the landscape was reacting.
25:32For nine months, the dam holds its water level at over 590 feet, producing 9,000 kilowatts of energy.
25:41For just one power station alone.
25:44But a 6,000 foot crack soon appears across the slope of Mount Tock.
25:49And on November 4th, 1960, a massive landslide happens.
25:55Over 24 million cubic feet of rock breaks off and slides into the reservoir just under 2,000 feet from
26:04the dam wall.
26:05Drastically increasing the water level, which could breach the crest of the dam.
26:12Providing you keep enough space in the level of the reservoir and this slow rock mass moves into it, it
26:18would not necessarily be a problem.
26:19They can control it.
26:21The engineers lower the water level, easing the pressure on the surrounding cliffs which stop the landslide.
26:27To control further land movement while also keeping the dam running, they raise and lower the reservoir level accordingly, causing
26:35fatigue in the process.
26:36So if you imagine taking a metal spoon and then you bend it back and forth a number of times,
26:43eventually that spoon is going to snap.
26:46So by raising and lowering the level of the water in the reservoir, they change the pressure exerted on the
26:54soil.
26:56Using the water level in the dam to control the surrounding land mass is risky.
27:01It makes it virtually impossible to predict how fast any landslide might react.
27:08Will this technique stop future landslides?
27:11And why was the Viant Dam abandoned?
27:26In Northern Italy, high in the Alps, is one of the tallest concrete barriers in the world, the Viant Dam.
27:34In 1960, engineers lower and raise the water in the reservoir to ease the pressure on the surrounding cliffs in
27:42order to save the dam and stop future landslides.
27:45The technique works.
27:48For three more years, the dam successfully supplies water to four power stations, producing much-needed hydroelectricity to fuel the
27:58economy of Northern Italy.
28:00And in April 1963, with the landslides under control, the engineers fill the reservoir behind the dam to its capacity
28:09at 2,345 feet above sea level.
28:14The lesson that civil engineers are reminded of time and again is to be acutely aware of the natural surroundings
28:23and the geology in which you are building your structure.
28:27Because if you don't take heed of those lessons, the price you pay could be devastating.
28:35Then, at 10.39 p.m., October 9th, 1963, disaster strikes.
28:43Over 9 billion cubic feet of rock breaks away from Mount Tock, hurtling down at 68 miles an hour.
28:52The destructive debris smashes into the reservoir below.
29:01It wasn't just the mass of earth that slid away into the reservoir.
29:06It was the ferocious speed at which it came.
29:1345 seconds for effectively half of the mountainside to drop into the water.
29:23It cascades into the water and causes big waves.
29:27Now, if you imagine a bath, you've got a wall on one side of the bath and you've got a
29:30lip the other side.
29:31You jump into that bath, you're going to cause waves in two directions.
29:35One will hit the wall and bounce back.
29:37That's exactly what happened in one part of the valley.
29:39The others can actually go over the rim.
29:41It is literally like an airborne tsunami.
29:45Over 800 million cubic feet of water becomes an 820-foot-high wave,
29:51with the village of Longorone in its path.
29:58A massive amount of water forced down such a tight gorge.
30:02It displaced all of that air, and it was almost like a shockwave of air.
30:06It hit the village directly before the water did and started destroying some of the buildings.
30:10And then next minute, a wall of water hits you.
30:14It's got rocks in it, it's got trees in it.
30:16It is like liquid sandpaper and it just wipes the village clean.
30:20Barely four minutes after the landslide begins,
30:24most of the town is obliterated by the subsequent wall of water.
30:29It is one of the worst natural disasters in European history,
30:33killing nearly 2,000 people.
30:37The tragic irony of this story is that,
30:40whilst the villages below the dam were completely destroyed by the onrush of water,
30:45the dam itself remained completely intact.
30:50I guess that's testament, really, to the quality of the design and build of the dam.
30:57It was just a dam built in the wrong place.
31:00The reservoir is ultimately filled with debris,
31:04and this spells the end for the great Vaillant Dam.
31:08It is abandoned.
31:10Today, the Vaillant Dam stands isolated in the rocky landscape,
31:16scattered with hints of its tragic past.
31:18It forms a permanent reminder of humanity's underestimation of the forces of nature.
31:26From an engineering perspective,
31:28the Vaillant Dam should have become one of the most impressive dams in history.
31:33Instead, it's become one of the most infamous.
31:36It's an unfortunate tragedy, but from tragedy we learn about how the landscape can react,
31:43and hopefully we can mitigate against such tragedies in the future.
31:51Over 500 miles across Europe, south of Dover on the British coast,
31:56is the quiet seaside village of Liddlestone that has a secret past.
32:04In the rough seas of the English Channel,
32:07a mysterious 200-foot-long and 32-foot-wide steel structure lies partially submerged in its waters.
32:16If you're one of the thousands of holidaymakers playing on the beach at Liddlestone,
32:20or even out for an early morning walk,
32:23you'd quite happily dismiss it as part of a sunken barge or something.
32:28The fact is, it's got far more historical significance than you could ever imagine.
32:35When the tide lowers to seven feet, it reveals some of its secrets.
32:41A large block of concrete nearly one foot thick, weighing over 6,000 tons.
32:47This bizarre object's humble appearance disguises its ambitious engineering.
32:54Imagine that the engineers at the time were a little bit worried that this was going to be a big
32:58risk to take.
33:01But what is this strange object?
33:04Why is it here?
33:05And why was it abandoned?
33:17In 1943, the largest seaborne invasion of the 20th century is conceived, D-Day,
33:24which calls for thousands of Allied troops and supplies to invade Nazi-occupied France in Normandy.
33:30But with the Germans heavily defending its major ports and harbors,
33:35where and how can the Allies land an entire invading army?
33:39It becomes obvious to the British, to the Americans,
33:44that it's immensely difficult to give an army the supplies it needs to keep on fighting
33:53once you've thrown them onto a beach.
33:55So, the Allies developed a unique and ambitious plan to supply the Allied forces.
34:02We, the Allies, brought together technology from the field of civil engineering, military engineering,
34:10materials science, to create something that had not existed before.
34:15An entire harbor that can move 60 miles to where it's needed.
34:22Codenamed Operation Mulberry, these floating harbors can only succeed
34:27if they have a particular critical component, the Phoenix caisson.
34:32The Phoenix caisson is but a tiny element of an incredibly complex,
34:37but at the same time brilliantly simple plan,
34:40to take a self-assembling floating harbor over to the beaches of Normandy for the D-Day landings.
34:47This watertight structure is designed to provide much-needed protection
34:52for the floating Mulberry harbors of the invading Allied forces.
34:56But with wartime steel shortages, engineers must turn to a more readily available material,
35:02concrete, which, amazingly, can float.
35:06The idea of using floating concrete blocks was actually nothing new.
35:11Concrete vessels had been made since the late 1800s.
35:16What was different was using them to create your own harbor,
35:20the size of any modern international ferry port.
35:24Each concrete block is five stories high.
35:28Intended to join together in a chain,
35:31they serve as the protective walls to the floating Mulberry harbors.
35:36The purpose of the Phoenix caissons was to act as a breakwater,
35:40as the outer limits of the harbor within which you'd have much calmer waters
35:45to land the supplies, the vehicles and the troops required on the beaches of Normandy
35:52for the D-Day landings.
35:54The caisson is made up of reinforced concrete,
35:57but it's the nine hollow compartments that hold the secret to its buoyancy.
36:02Its volume consists of a shell of concrete combined with an element lighter than water, air.
36:09Weighing less than the water it displaces, this concrete block is able to float.
36:14Equipped with C-valves through which each compartment can be flooded,
36:18these mobile blocks can be sunk wherever they are needed to become immovable.
36:24The Phoenix caisson itself rates quite high in terms of the engineering ingenuity involved in World War II.
36:32The engineers knew they had a job to do and they solved it very efficiently and very beautifully.
36:38Construction begins in late 1943.
36:42Workers must make 212 caissons with only six months to complete this colossal task.
36:49At 12 different coastal locations around Britain, 45,000 laborers work in complete secrecy
36:57to construct the caissons that require over 8 million cubic feet of concrete and 31,000 tons of steel.
37:07A lot of the people will be out there fighting the wars and so on, so you get the unskilled
37:11labor in
37:11and you can actually train them up quite quickly to fix steel, to pour the concrete,
37:16because actually the process of doing that is not terribly technical or complicated.
37:23To keep a project of this magnitude under wraps, the engineers used the caissons design and function in a daring
37:30way.
37:32To keep the plans for the D-Day landings a complete secret from the Germans,
37:36once the Phoenix caissons had arrived at their assembly point on the south coast,
37:40they were sunk to keep them out of view below the water level.
37:44The idea being then that you'd pump the water out to float them up before being towed over to France.
37:50In a mere six months, 212 Phoenix caissons are built and many are sunk in the English Channel in preparation
37:58for D-Day.
37:59Now, true to their name, they must rise again to play their part in the invasion of Normandy.
38:05Of course there's always the chance that once you've done the first sink,
38:09it actually does what it's supposed to do and sticks into the ground and then stays there nice and stable
38:14against the sea currents.
38:16Will engineers get all the caissons to refloat? How will they work during the invasion? And why was the Phoenix
38:24caisson abandoned?
38:35Off the British coast lies the unsung hero of D-Day, the Phoenix caisson.
38:41On June 7th, 1944, within 24 hours of the Allied invasion of Nazi-occupied France, the troops need supplies and
38:51fast.
38:52This is the moment for the Phoenix caisson to rise.
38:55The majority of the giant concrete breakwaters hidden under the English Channel are successfully refloated.
39:01The Allies sail them across to the Normandy beaches to play their part in the invasion.
39:08The Phoenix caissons had a crew of six men.
39:13I mean, imagine that, being a crewman on board a floating piece of concrete.
39:18As they were towed along by tugboats, on board was a little accommodation hut, a life raft in case anything
39:25went wrong.
39:26But they also had anti-aircraft guns, just in case they came under attack.
39:32At a rate of three knots, it takes 30 hours to float 146 of these giant concrete caissons to the
39:41secured beachheads of Omaha and Gold.
39:44Once sunk in place, they act as a two-mile-long breakwater and outer wall of the harbour, fulfilling their
39:51crucial role in Operation Mulberry.
39:54Concrete boxes of the Phoenix caisson in and of themselves are not terribly impressive when described as a concrete box.
40:01But the usage of that caisson in landing material, men and equipment on the beaches of France was tremendously important.
40:10The Mulberry Harbour makes up an area of 500 acres that is protected by a ring of Phoenix caissons.
40:18Critically, they calm the waters so boats can safely dock at the floating piers, whether at high or low tide.
40:25Having taken the Germans by surprise, the Phoenix caissons evade serious bombardment.
40:32Designed to last only 90 days, the Mulberry Harbours in France are still going strong 10 months later.
40:39With the help of the Phoenix caissons, the Allies are able to unload 2.5 million men, half a million
40:46vehicles and 4 million tons of goods and supplies.
40:50To the engineers involved, the Mulberry Harbours were a phenomenal success.
40:55D-Day landings have been described as one of the most monumental events in modern history.
41:01The Phoenix caissons are a huge part of that.
41:04But not all the caissons are successful. Many don't make it.
41:09And off the coast of Littlestone, no matter how hard the engineers and pumps work on the stranded caisson beached
41:15there, it refuses to rise to the surface.
41:19The only problem was, in certain areas, the seabed was extremely sticky.
41:25And try as they might, the Phoenix caisson at Littlestone just couldn't be floated again.
41:31Unable to rise from its watery grave off the shore of England, it lies abandoned.
41:38The Phoenix caissons played a crucial role in the Allies winning World War II.
41:43And are now a monument to military ingenuity and inspiration for generations of civil engineers to come.
41:51The story of the Phoenix caisson at Littlestone, in a way, is a story of failure.
41:56It never made its way over to France.
41:58But if you were able to get it off the seabed today and float it, it would still be able
42:03to do the job it was designed to do.
42:05And that's testimony to quality engineering and a sound plan.
42:13The Phoenix caisson at Littlestone
Comments