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In the aftermath of a tsunami disaster,

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can underwater robots succeed where no humans can go?

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This is a robot in highly radioactive water.

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It's like three levels bad.

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How did a shipwreck end up perfectly preserved

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on the bottom of the Great Lakes?

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She is completely intact.

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It was almost as if it had been sort of gently placed

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on the bottom of the lake.

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And what's the dark secret buried inside a toxic Nazi submarine?

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There is a ticking time bomb at the bottom of the ocean here.

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The underwater realm is another dimension.

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It's a physically hostile place where dreams of promise

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can sink into darkness.

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I'm Jeremy Wade.

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I'm searching the world to bring you the most iconic

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and baffling underwater mysteries known to science.

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Shipwrecks can't just disappear, or can they?

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It's a dangerous unexplored frontier that swallows evidence.

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We know more about the face of Mars than we do our deepest oceans.

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Where unknown is normal and understanding is rare.

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The most extreme force in the ocean, the tsunami,

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has killed hundreds of thousands of people over the centuries

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and wrought destruction across the planet.

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And the most powerful man-made force on Earth, nuclear energy,

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has wrought destruction across the planet.

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And the most powerful man-made force on Earth, nuclear energy,

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has wrought destruction and death in equal measure.

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So what happens when these two forces meet?

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In Japan, this clash has led to a toxic mystery

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that science is still struggling to solve.

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March 11th, 2011.

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Approximately 45 miles east of Japan,

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deep beneath the Pacific,

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a magnitude-9 megathrust earthquake rips through the ocean floor.

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Japan is basically sitting right on top of the Pacific Rim, the Ring of Fire.

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It's a whole series of deep underwater trenches

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where one tectonic plate is moving underneath another.

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The Pacific plate goes under the Japan plate

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and it's snapped up, almost 100 feet in places.

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The earthquake is so powerful,

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it moves the main island of Japan 8 feet to the east

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and shifts the Earth on its axis by over 6 inches.

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There was the largest earthquake they had recorded there in many centuries.

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But this natural disaster is only just beginning.

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The earthquake created a huge series of waves,

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tsunami waves or tidal waves,

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that basically raced toward the mainland of Japan.

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45 minutes later, waves over 40 feet high

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and traveling in places at speeds of several hundred miles per hour hit land.

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The harbor has this tsunami wall

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and you just see the water rise up,

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go to the top of that tsunami wall

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and just pour over into the town.

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Cars are flipped around like toys,

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buildings are completely flooded and smashed,

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people are swept away at a moment's notice.

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It's just, it's a nightmare.

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They were prepared for tsunamis.

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They were not prepared for that tsunami.

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Sitting right in the path of the oncoming tsunami

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is the Fukushima Daiichi Nuclear Power Plant.

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It flooded the plant much higher than they ever expected.

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The plants were designed for a 18 foot high tsunami wave.

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What actually hit them was 45 feet.

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So it was three times higher than they ever expected.

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It's an absolute disaster.

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Who could anticipate something like this?

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The angry ocean torrent floods the emergency generators,

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cutting electricity to the cooling system

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that keeps the nuclear reactor cores at a safe temperature.

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And the cores overheated.

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The gas built up inside, the pressure's increased

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because they could not cool it.

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It ignited with a spark somewhere.

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And two of the buildings exploded.

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All three reactor cores largely melt.

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Then, like lava from a volcano,

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they pour through six inches of steel at the bottom of the reactor

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and down into concrete.

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I report it was hell on earth sometimes,

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with those operators in the control room,

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in the dark wearing protective equipment,

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trying to figure out what they were going to do.

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Millions of gallons of sea water are urgently pumped in

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to cool the core temperatures down to a safe level

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and prevent the release of more radioactive gas.

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The biggest concern in this situation, of course,

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is the sort of exposure and release of radioactive materials

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from the nuclear facility.

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Leaks from the plant are not without precedent.

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In previous spills,

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thousands of tons of contaminated water have leaked into the ocean.

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But it's the water around the destroyed reactors

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that poses the most immediate problem.

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There's different levels of water in the three reactors.

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One of them is the water level is low,

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the other one, the water, is about two feet deep,

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and the other one is about nine feet deep.

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So the molten core is underwater

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and there's always water being injected on it to keep it cool.

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Not only did water cause untold damage when it consumed the plant,

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it's now stubbornly getting in the water.

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It's now in the way of the cleanup,

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and it's incredibly dangerous.

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You have all this water around that radioactive material,

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which in itself becomes radioactive.

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Sending divers into the radioactive underwater areas is not an option.

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The radiation levels are excessively high,

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so it would be fatal to go inside.

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So another solution needs to be found and fast,

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because until it's contained,

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there remains the risk of radioactive runoff leaking into the ocean.

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How do the Japanese take care of this environmental disaster

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waiting to happen?

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Years after a tsunami floods the Fukushima nuclear facility,

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almost a thousand tons of radioactive material lie scattered

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and submerged in the bowels of the power plant.

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Can new technology speed up the critical cleanup operation

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to halt the spread of radioactive contamination to the ocean?

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With the distance to Pacific being just 100 yards,

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another earthquake could very easily cause a disaster

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far greater than this one.

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So the team is under a constant pressure to get the control

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of the radioactive material and get it to a safe place.

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They're not cleaning up.

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They're figuring out how to clean up.

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Technicians are struggling to solve the problem,

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but so far they've been unable to even reach the reactor cause.

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It requires technology beyond cleaning crews and human cleanup.

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This is not a first.

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In 1979, the Three Mile Island facility in Pennsylvania

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suffered the worst nuclear accident in US history.

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Lake Barrett was a director of the plant.

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In the case of Three Mile Island,

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we had several million gallons of highly radioactive water.

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We had to develop specialized cleanup systems.

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Faced with a molten core submerged in water,

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Lake's team employed a pioneering solution for the time,

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robots.

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We had robots at Three Mile Island, very crude robots, 1980s robots.

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We were able to develop the equipment to remove the core,

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and over the next seven years of work,

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and it was successfully removed.

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But this operation required international assistance.

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We were reaching out to the world for help.

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The only one country in the world came to our aid in Japan.

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So when I was asked to help them,

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I felt that it was not necessary to do that.

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Could the solution found in the US, robots, be the answer at Fukushima?

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In theory, this sounds pretty straightforward.

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Let's create some robots that can go in and photograph and clean up.

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The practical reality is much more complicated.

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The meltdown caused by the tsunami has created a no-man's land inside the reactors,

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an uncharted lethal landscape, much of it underwater,

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that the robots will need to navigate.

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The robots have to be small to go inside the reactor vessel.

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And it's complicated work to get these small ones to work and do what you want.

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Wi-Fi and radio signals do not work in there

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because of the thick reinforced concrete walls.

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Finally, a robot is ready.

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Known as Scorpion, it has cost tens of millions of dollars to develop and put into operation.

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They had a camera come up like a tail of a scorpion over the front.

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It went about 10 feet and it got caught on debris.

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It couldn't get down into the molten core area.

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This was a multi-million dollar mistake.

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It's back to the drawing board.

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Other robots follow, but with limited success.

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They were supposed to work, we thought, for about eight hours.

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They worked for about an hour and a half before the radiation basically fried the circuits inside.

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The robots fail to get near the reactor cores.

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You learn more from a failure than from a success in many ways.

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Eventually, designers come up with an underwater robot called Little Sunfish.

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Its task is to navigate into the heart of the flooded reactors.

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The Sunfish was a small tethered submarine with cameras on it, about five inches in diameter,

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that had to swim down through a little doorway underneath the reactor vessel.

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Sunfish enters an underwater realm like no other.

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Finally, it glimpses something through the murky water.

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Almost stalactite-like formations dripping like candle wax.

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You can see pieces of fuel and you can see molten debris.

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This was the first time we got to see that, so everybody was very excited about the success of it.

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With this breakthrough, the cleanup team can now look to build bigger muscle robots to remove the debris.

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Without this technology, without robots, this would not be possible.

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But developing and deploying this advanced robot fleet to clean up Fukushima is a major long-term challenge.

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The cost of this is going to be large. It's going to be about $200 billion.

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And the technical cleanup of the site itself is going to be multi-decade.

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Until the cleanup is complete, Fukushima will remain a potential radioactive risk to the neighbouring ocean.

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And the ocean itself remains a clear and present danger to the plant.

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What happens if there's enough earthquake, another tsunami, and we haven't dealt with this in time?

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One thing we do know is that we underestimate the forces of nature,

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whether the untamed power of the ocean or the harnessed energy of the atom, at our peril.

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I've dived on numerous shipwrecks and many adjust that.

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Rotted, rusting wrecks.

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But on rare occasions, the depths offer up that holy grail of marine archaeology, the wreck that's perfectly preserved.

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With all the evidence intact, unraveling the mystery of what happened to the ship should be easy.

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Or so you'd think.

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1986. Lake Huron. The second largest of the Great Lakes.

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Shipwreck hunters are exploring the waters in the northwest of the lake

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when they make a jaw-dropping discovery.

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A schooner, more than 100 years old, frozen in time on the lake bed.

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She is completely intact.

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The masts are still up. The rings that hold the sails that go up the mast are still in place.

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The cargo of grain is still in the hole.

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This vessel is in pretty spectacular condition.

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It was almost as if it had been sort of gently placed on the bottom of the lake.

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What sank this perfectly preserved wreck?

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A perfect, undamaged shipwreck has been found at the bottom of Lake Huron.

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But what happened to her?

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How is it that this great ship is pristine, in condition, resting on a lake bed?

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On the ship's side, divers have been able to find the shipwreck.

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The Cornelia B. Windyott.

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She's a 136-foot schooner that went missing with all hands during the November storm season of 1875.

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The Great Lakes take their fair share of ships.

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Six thousand shipwrecks litter the beds of these huge lakes.

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The Great Lakes are the first to be found in the Great Lakes.

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They take their fair share of ships.

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Six thousand shipwrecks litter the beds of these huge lakes.

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And over 30,000 lives have been lost.

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If a vessel is in a storm, usually that storm creates havoc on the vessel.

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It can rip things off the deck, tear things apart, bust masts, things like that.

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None of that is seen on the Windyott.

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If that ship had sunk in a storm, you'd expect it to be smashed to pieces.

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As well as no signs of damage, there are no signs of any crew.

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We don't know where the crew are. There are no bodies associated with it at all.

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But we do know that they didn't make a standard maritime escape.

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Lying in perfect condition on the lake bed is the schooner's single lifeboat.

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What happened to the Windyott and her men?

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One thing is certain, the ship sank.

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Why or how it sank is a little bit more unclear.

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In the 1870s, Lake Huron was part of a valuable grain route.

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We know the vessel left Milwaukee, loaded with tons of grain.

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She was heading to Buffalo, one of the great grain centers on the Eastern Great Lakes.

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A November sailing carried weather risks.

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But with fewer voyages being undertaken at this time of year,

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it's likely there would have been a financial incentive for the crew.

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The area depends on this kind of trade, and there would be nothing worse than a bunch of rotting grain,

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especially at the end of the season.

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It appears that the Windyott was leaving nothing to waste.

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Port records show that on departure, she was overloaded with 30% more cargo than usual.

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During her voyage, the Windyott would likely have encountered gale force winds

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and temperatures down to minus 10 degrees or colder.

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So is it possible that the freezing weather provided an unexpected escape route for the missing crew?

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Because it was cold weather, perhaps the ship itself got stuck into ice,

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and the crew tried to leave the ship.

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Such an escape is not without precedent.

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In winter, the Great Lakes are prone to freezing, and thick ice could have provided a route to shore.

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But one piece of evidence suggests the Windyott crew did not simply walk off the ship.

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Now the lifeboat has been left behind. Knowing that the ice is sometimes treacherous,

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you would have expected to have possibly taken a lifeboat with them.

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And the latest analysis of wind directions suggests that a significant lake freeze didn't happen in this period.

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So getting stuck seems unlikely.

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And even if that did happen, the force of ice crushing it from all sides would be evident on the Windyott's remains.

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Which are undamaged.

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But could a much more recent tragedy on the high seas provide a new lead in solving this puzzling mystery?

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2017, the Bering Sea in the Northern Pacific Ocean.

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Seattle-based Crabboat, the destination, sails into severely cold and rough conditions.

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They didn't even have time to react before the vessel capsized and sank.

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Six people were killed.

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A key cause of the sinking was found to be a buildup of ice on the boat.

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In very cold conditions, when you have waves and you have spray, this spray will turn into ice droplets and start to cover things with ice.

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It just builds up layer after layer, wave after wave comes crashing in.

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Until it reaches a point where it just overtakes the vessel.

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So could a buildup of spray ice have sunk the Windyott?

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The 19th century scoona, the Cornelia B. Windyott, is found undamaged on the bottom of Lake Huron.

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Could ice build up the phenomenon that sank an Alaskan fishing vessel be to blame?

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It's this same deadly phenomenon that they were caught with sea spray icing so quickly and so perilously that they sank and didn't even have time to react.

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The Windyott was a sizable vessel capable of carrying large quantities of heavy cargo.

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So could ice really have taken her down?

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With the weight of ice on the top of the vessel rather than at the bottom of the vessel, you have these huge issues with weight distribution.

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And when the vessel goes over, there's no writing moment from the bottom of the vessel to stop that ice from pulling down. Gravity is actually working against the vessel.

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And in the fresh waters of the Great Lakes, another factor would have been working against the Windyott.

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Fresh water would freeze quicker than salt water. There is a possibility of having that ice buildup just from the wind.

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Experts have calculated that the rate of fresh water ice buildup on the day of the Windyott sinking could have reached as much as 16 tonnes per hour.

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The only kind of defences that crews have is going out and actually breaking it off by hand.

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Using hammers, wedges, anything they have to kind of beat back the ice and outrun Mother Nature itself.

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And spray ice on the decks may account for another element in the Windyott mystery. The missing crew.

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You're on a moving ship. The crew would have been sliding across it.

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Meaning that they were actually washed off the ship. The spray which was adding ice to the ship actually got rid of them.

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Whether or not the ice sent the crew sliding to their deaths, it may have played an even more surprising role.

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It could be responsible for the remarkable preservation of the Windyott wreck.

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So when it's covered with the ice that adds enough weight to sink it. But the ice of course is also slightly buoyant.

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So that is why she ends up having a nice smooth glide to the bottom of the seabed. In fact she might have even sat there suspended in the water for a bit.

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The ice just melts away and boom, you have your perfect ship at the bottom of the lake bed.

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And this is how she was found over a hundred years later. But there's no way of knowing for sure that ice was what sank the ship.

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The trouble is there'll be nothing for us to discover that proves the ice. Because the ice of course is mostly made up of the water which has existed around the Windyott now for hundreds of years. So it's a theory.

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Further examination of the Windyott may in time offer up other answers. For now we're left with just the scene of the crime. The prime suspect has melted away.

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The history of naval warfare is a record of winners and losers. But do historians ever record the wrong result? A recent underwater discovery in the Mediterranean Sea suggests just that.

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Could it lead to a radical reinterpretation of the history of the ancient world?

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In 2002 a fisherman trawling off the western coast of Sicily in the Mediterranean Sea is astonished to pull up not a fish but an artifact from another world.

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The massive solid cast piece of bronze.

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Stunned marine archaeologists recognize the mystery item as something that's never been found in the ocean before. A battering ram from an ancient warship more than two thousand years old.

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The bronze battering ram at the front of these ships was the height of technology of its period. It was the Tomahawk cruise missile, the Trident ballistic missile of its period. We're talking something which could weigh in itself up to a tongue.

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Ancient battering rams were designed to inflict the maximum amount of damage to enemy vessels.

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These rams are built with kind of three fins that angle out. These fins are meant to spring the planks of the enemy ship and tear them at the seams so that the rest of the ship kind of becomes undone almost like a zipper.

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It's the tip of a spear magnified a million times and you know you have all that weight, all that speed, all that pressure. Pretty irresistible of course.

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It's like nothing else that has been found in antiquity.

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The dramatic discovery prompts a major archaeological survey. What they discover is extraordinary. A site spread over an area the size of Manhattan.

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And within it the remnants of one of the most important naval battles of antiquity. The battle of the Agates, also known as Agadi.

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The battle of Agadi was between the Romans and the Carthaginians.

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The Romans at the time are expanding their sphere of influence throughout Italy. They found that they were confronting the major local power than Carthaginians.

301
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This battle is considered a really critical moment in military naval history because the Romans weren't really known for winning at sea.

302
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But according to all written records from the period the Romans were victorious.

303
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The battle of Agadi basically put the Roman Republic on the map.

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This is a big pivotal moment where Rome finally goes from a regional power to kind of a Mediterranean maritime power.

305
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The traditional interpretation of the result and importance of the battle of Agadi has been accepted for over 2,000 years.

306
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But when they study the battle site marine archaeologists find evidence that suggests a very different story.

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The battering ram, the exceptional item first recovered from the Agadi site, turns out not to be the only one.

308
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This is a really unique site in the sense that multiple battling rams have been found.

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Until now only three of these rams were known to be in existence anywhere in the world and none were found where they fell.

310
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But as marine archaeologists comb the Agadi site they are amazed to discover more than 20 of these ancient weapons.

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Battering rams would have been used by both sides in the battle of Agadi but with different features and designs.

312
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The unique type of alloy and the quality of these rams you can pinpoint which ones are Roman.

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The number of rams found on the sea floor gives an indication of the number of ships that were sunk in the battle.

314
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But remarkably when archaeologists do the math they can confirm that only one of the rams comes from Carthage but a staggering 15 are Roman.

315
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How these Roman rams are at the bottom of the sea.

316
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Instead of being as history tells us the naval victory that founded an empire did the Romans in fact lose the battle of Agadi.

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History has recorded a great victory for the Romans at the naval battle of Agadi.

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But recent finds in the seas of Sicily suggest something very different.

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When we find something that doesn't fit our expectations maybe some of our theories are incorrect.

320
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Maybe we need to reconsider how we understand that timer or that battle.

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In this period despite being a great force on land the Romans scored few victories at sea.

322
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This is something that the Romans were not considered to be the experts at this.

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And so during this battle the advantage was not on the Roman side.

324
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The Carthaginians had an unrivaled reputation as master mariners and naval tacticians.

325
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And in the Battle of Agadi the Roman force was less than half the size of the Carthaginian fleet of up to 700 ships.

326
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The underdog in this fight is the Romans. They have been the losers at just about every battle with the Carthaginians up to this point.

327
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So did the Romans in fact lose as suggested by the number of rams discovered on the sea floor.

328
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Or could there be another reason why the remains of so many Roman ships were found at the Agadi site.

329
00:31:02,000 --> 00:31:11,000
Building a warship is very expensive. Therefore you go to every measure to make it as cost effective as possible.

330
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And the easiest way to do that is to use a captured ship.

331
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A lot of the Roman ships that are we're finding here at this battle are actually reused ships that were captured about nine years previous at another naval battle where the Carthaginian side was actually victorious.

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Capturing ships and putting them to work in your own fleet is a tactic that's been employed by navies throughout the centuries.

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The British Navy for example captured many friendships and used them afterwards as part of their own fleet.

334
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The theory that Carthage was using captured Roman vessels at Agadi would explain why so many Roman rams have been found.

335
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And it tallies with the historical account of a Roman victory.

336
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But with much of the Agadi sites still to be excavated a definitive answer could be years away.

337
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Every year that we go back every time that we actually do surveys there and find new things the questions just get exponentially bigger.

338
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With new technology we're uncovering more and more wrecks from further and further back in time.

339
00:32:18,000 --> 00:32:22,000
I wonder what re-readings of history remain to be discovered.

340
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The dark frigid lifeless ocean depths have often been considered a good place to hide our unwanted secrets.

341
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But a danger hidden is rarely a danger resolved such as the case with the 75 year old mystery of the toxic Nazi submarine.

342
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February 1945 the closing months of World War Two.

343
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With defeat in Europe looming Hitler orders one of Nazi Germany's fleet of long range U-boats to carry out a top secret underwater mission.

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This is the end of the Second World War. The Germans are beginning to transport some of their secrets from the Third Reich.

345
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The hope being that some of its leading edge cutting edge keynotch secrets can find a way to be used from a new home in Japan.

346
00:33:28,000 --> 00:33:33,000
The Nazi goal is to help the Japanese change the course of the war in the Pacific.

347
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If the sub got to Japan it would have given Japan technology that may have helped them resist the Americans.

348
00:33:43,000 --> 00:33:45,000
The operation requires the utmost secrecy.

349
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If you have something that you really want to keep well hidden a submarine was an ideal form of transportation.

350
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What the Germans don't know is that British code breakers at their Bletchley Park HQ have cracked the Nazis enigma code.

351
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Hitler's top secret mission is no longer a secret.

352
00:34:12,000 --> 00:34:18,000
From the Allies point of view they didn't know exactly what was on the submarine but it was absolutely critical they find it and destroy it.

353
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They intercepted these communications which indicated to them that this had potential implications for the outcome of the war.

354
00:34:29,000 --> 00:34:38,000
And the British have another key advantage. One of the German submarines engines is faulty and it's emitting a noise that can be tracked.

355
00:34:39,000 --> 00:34:44,000
And there's this cat and mouse chase up the Norwegian coast.

356
00:34:44,000 --> 00:34:54,000
Like hunting down wounded prey British submarine HMS Ventura stalks you 864 through the freezing murky depths of the North Sea.

357
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Ventura is finally at a point where it has no choice. It's afraid that it's going to lose the 864.

358
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So the British sub quickly launches four torpedoes.

359
00:35:07,000 --> 00:35:15,000
It's easy to sink a ship on the surface for a submarine to sink another submarine is unheard of.

360
00:35:17,000 --> 00:35:24,000
The first three torpedoes miss but the fourth finds its target.

361
00:35:28,000 --> 00:35:33,000
A massive explosion rips through the midsection of the German U-boat.

362
00:35:34,000 --> 00:35:41,000
This is the only time in history a submarine submerged using a torpedo has sunk another submarine.

363
00:35:42,000 --> 00:35:47,000
The captain of the ship would say probably skilled but 90 percent of the rest of the world would say heck that's a lot of work.

364
00:35:49,000 --> 00:35:55,000
U 864 sinks in 500 feet of water with all 73 crew on board.

365
00:35:56,000 --> 00:35:59,000
For the British Navy it's job done.

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00:36:00,000 --> 00:36:05,000
But for the Norwegians in whose waters the wreck of the German sub lies it's a different story.

367
00:36:06,000 --> 00:36:11,000
Because of the materials that were known to be aboard it was secret military materials.

368
00:36:12,000 --> 00:36:14,000
It was always a priority to try and find her.

369
00:36:16,000 --> 00:36:19,000
She's finally found after 70 years.

370
00:36:20,000 --> 00:36:21,000
But there's a problem.

371
00:36:22,000 --> 00:36:27,000
There are over 1800 canisters full of liquid mercury.

372
00:36:29,000 --> 00:36:32,000
The Nazi sub is toxic.

373
00:36:44,000 --> 00:36:50,000
When German U-boat 864 sinks in the closing stages of World War Two she remembers the fact that the U-boat was in the water.

374
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And remains hidden in the darkest depths of Norway's North Sea for over 70 years.

375
00:37:00,000 --> 00:37:04,000
It's not until 2003 that the wreck is discovered.

376
00:37:06,000 --> 00:37:11,000
A Norwegian Navy minesweeper using unmanned underwater vehicles discovered the submarine on the seabed.

377
00:37:12,000 --> 00:37:16,000
And it found the submarine was in two major portions with a spread of debris around it.

378
00:37:16,000 --> 00:37:21,000
Is the sunken Nazi U-boat finally ready to give up her wartime secrets?

379
00:37:22,000 --> 00:37:29,000
The difficulties of doing recoveries on a military site the obvious one is well this is a German submarine at war.

380
00:37:30,000 --> 00:37:32,000
How many torpedoes are still left in the vessel?

381
00:37:33,000 --> 00:37:38,000
U-864 is thought to contain over 20 high explosive torpedoes.

382
00:37:40,000 --> 00:37:43,000
But there's something even more dangerous waiting on the underwater wreck.

383
00:37:44,000 --> 00:37:51,000
By 2003 Norway is in possession of the original 1945 manifest for the Nazi sub's final voyage.

384
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And it reveals a particularly sinister cargo.

385
00:37:57,000 --> 00:37:58,000
Mercury.

386
00:38:00,000 --> 00:38:05,000
1857 canisters which equates to over 65 tons.

387
00:38:06,000 --> 00:38:10,000
Enough poisonous liquid metal to cause an environmental catastrophe.

388
00:38:10,000 --> 00:38:15,000
And once in the food chain a serious danger to human life.

389
00:38:16,000 --> 00:38:20,000
Mercury is a neurotoxin. It's bad for the brain for your neural system.

390
00:38:21,000 --> 00:38:25,000
It can cause dizziness, loss of function in your muscles.

391
00:38:26,000 --> 00:38:29,000
You can't walk, you can't talk, slurs your speech.

392
00:38:31,000 --> 00:38:37,000
Before they can even think about recovering this lethal liquid, scientists face a more immediate challenge.

393
00:38:38,000 --> 00:38:45,000
A major problem with the project is that the submarine is lying on the bottom of a shelf.

394
00:38:46,000 --> 00:38:49,000
So it's sloping off into the deep Atlantic.

395
00:38:50,000 --> 00:38:53,000
Part of the submarine could actually slide to a deeper depth.

396
00:38:54,000 --> 00:39:02,000
If the U-boat slips it could release all the toxic mercury into the sea potentially poisoning an entire ecosystem.

397
00:39:03,000 --> 00:39:08,000
And it's not stable. At any time it can kind of fall apart. Something has to be done.

398
00:39:10,000 --> 00:39:14,000
So the key thing to start with is to actually stabilize the submarine.

399
00:39:15,000 --> 00:39:18,000
So a platform, a shelf, is being built underneath the submarine.

400
00:39:19,000 --> 00:39:22,000
The operation is further complicated by the depth of the wreck.

401
00:39:24,000 --> 00:39:28,000
At over 500 feet down it's too deep to send divers.

402
00:39:29,000 --> 00:39:35,000
So a brand new remote system is designed to stabilize the sub using gravel ballast.

403
00:39:37,000 --> 00:39:43,000
It's not like you can just take a big ship load of gravel and just dump it off the side of the ship.

404
00:39:44,000 --> 00:39:48,000
It has to strategically be placed using technology.

405
00:39:49,000 --> 00:39:57,000
An ROV basically is almost sort of like a garden hose in that it's spraying small gravel or very coarse sand.

406
00:39:58,000 --> 00:39:59,000
It's stabilizing the wreck.

407
00:40:00,000 --> 00:40:03,000
The stabilization of U-864 is successful.

408
00:40:04,000 --> 00:40:08,000
But despite this there are indications that the mercury may be spreading.

409
00:40:09,000 --> 00:40:15,000
We are detecting leaks of this mercury right now. How much has already leaked out? How much is safely contained?

410
00:40:16,000 --> 00:40:19,000
The recovery process itself might actually spread the mercury around.

411
00:40:20,000 --> 00:40:22,000
You might disrupt the canisters, you might break them.

412
00:40:23,000 --> 00:40:27,000
So it's a catch-22. If you do you could be damned. If you don't you could be damned.

413
00:40:28,000 --> 00:40:32,000
But the salvage team think something even more deadly may be on board.

414
00:40:33,000 --> 00:40:39,000
So the speculation at the time was that the U-864 could have been carrying enriched uranium.

415
00:40:40,000 --> 00:40:44,000
Enriched uranium is the vital element in nuclear bombs.

416
00:40:45,000 --> 00:40:50,000
Thankfully testing around U-864 does not show traces of uranium.

417
00:40:51,000 --> 00:40:54,000
But it's another threat that must be considered by the salvage team.

418
00:40:55,000 --> 00:41:04,000
With the toxic danger of the wreck thought to be too great to attempt to raise it to the surface, other options are being considered.

419
00:41:05,000 --> 00:41:10,000
Another way the Norwegians are looking at is to cover it in a sarcophagus.

420
00:41:11,000 --> 00:41:14,000
I want to say a post-Chernobyl approach.

421
00:41:15,000 --> 00:41:18,000
Encapsulate it in a giant concrete cap.

422
00:41:18,000 --> 00:41:26,000
One plan proposes that the toxic submarine be given an underwater burial beneath 40 feet of concrete and gravel.

423
00:41:27,000 --> 00:41:30,000
But locals are concerned that the mercury will still pose a threat.

424
00:41:31,000 --> 00:41:39,000
So the solution to a toxic problem created by Allied action at the end of World War II remains elusive.

425
00:41:40,000 --> 00:41:45,000
The mystery for us here is we still don't know exactly what we're dealing with within the submarine.

426
00:41:45,000 --> 00:41:47,000
And once we do know what to do with it.

427
00:41:50,000 --> 00:41:58,000
There have been rumours over the years that in addition to its toxic cargo, U-864 may have been carrying Nazi gold.

428
00:41:59,000 --> 00:42:02,000
Or even the last will and testament of Adolf Hitler.

429
00:42:03,000 --> 00:42:10,000
But until we find a way of accessing the wreck safely, all of this will remain a tantalising mystery.