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00:00:03In 1938, the Third Reich is in ferment as Hitler prepares to plunge Europe into war.
00:00:14Within months, the German army will begin a top secret research program to develop nuclear weapons.
00:00:24It is based on experiments performed in Berlin that showed for the first time that the atom can be split,
00:00:31unleashing immense power.
00:00:39German scientists were the first to start work on the atom bomb, but they would never finish the job.
00:00:49Just why has always been a mystery.
00:00:56In search of clues to solve this mystery, a team of underwater archaeologists has come to this lake in Norway.
00:01:05They're looking for the cargo that was on board this sunken ferry.
00:01:11Look at that.
00:01:13There's something there, isn't there?
00:01:15Is the key to the Nazi nuclear bomb about to emerge from the icy depths of a Norwegian lake?
00:01:24Hitler's sunken secret.
00:01:26Right now, on NOVA.
00:01:49For sixty years, the icy waters of Norway's Lake Tin have held a secret.
00:02:00Today, its peaceful shores show little sign of the conflict that raged here in World War II.
00:02:13But under Nazi occupation, this region witnessed a deadly underground war of spies and saboteurs.
00:02:22The battle was for one thing above all, a mysterious substance called heavy water that the Norwegian resistance fought desperately
00:02:33to keep out of German hands.
00:02:38In 1944, in a daring act of sabotage, a passenger ferry carrying several barrels of heavy water was sent to
00:02:49the bottom of Lake Tin.
00:02:54Now, a team of underwater archaeologists is looking for those barrels.
00:03:02They want to know what's really inside them.
00:03:07Because they may contain the key to the only weapon that could have won the war for Hitler.
00:03:12A Nazi nuclear bomb.
00:03:27The story begins on April 9th, 1940, when Nazi Germany invaded the small, neutral country of Norway.
00:03:39Taken by surprise and betrayed by Nazi sympathizers in their own government, the Norwegians could offer little resistance.
00:03:51As opposition crumbled, the Germans headed straight for the remote area around Lake Tin to take control of Norway's most
00:03:59valuable industrial enterprise.
00:04:04High in the mountains, at the head of the Rukan Valley, was the Bamork hydroelectric plant, once the world's largest
00:04:11power station.
00:04:15The Norsk Hydro Company used that power to make ammonia, the basis of fertilizer and explosives, both vital to the
00:04:23German war effort.
00:04:28But inside the Norsk Hydro plant was a room of specialized equipment that made something even more valuable.
00:04:40Where are we here then?
00:04:42Well, look here, the original stuff, the high concentration cells.
00:04:47Physicist and historian Per Dahl is an expert on what happened here during World War II.
00:04:53We are really looking here at the piece of history, the original high concentration cells for producing heavy water.
00:05:02Heavy water was a strange new form of water that had only recently been discovered.
00:05:09And Norsk Hydro was making small quantities to supply scientists around the world who were investigating its properties.
00:05:21As soon as they took over the plant, the Germans set about increasing production.
00:05:27They doubled the production apparatus, expanding the high concentration cells from the initial 9 to 18, doubling the production.
00:05:39By 1942, they were seeking a tenfold increase in the production of heavy water.
00:05:45At the same time, the security around the plant in Rukan was drastically heightened as well.
00:05:55Nobody could understand why.
00:06:00But every move the Germans made was being watched both inside the factory and out.
00:06:13A group of us, particularly the organized labor at the factory, wanted to create a movement to fight the Germans
00:06:21underground.
00:06:21All stillness.
00:06:24Canute Lear Hansen became a key member of the secret resistance, determined to figure out the German obsession with heavy
00:06:32water.
00:06:37The heavy water.
00:06:39We had no idea at all what it really was and why the Germans paid so much attention to it.
00:06:45It had to be something important.
00:06:52The resistance communicated its concern to British intelligence in London.
00:07:00The home forces had established a radio station, so there was a steady stream of messages sent to England by
00:07:06radio.
00:07:08To the British, the developments at Vamork were deeply alarming.
00:07:13They knew something the Norwegians didn't.
00:07:16But heavy water could be used to make nuclear explosives.
00:07:21It looked as if German scientists were trying to build an atomic bomb.
00:07:29If I were a physicist in London and realized what was going on in Norway with the heavy water business,
00:07:37I would have been mighty worried.
00:07:39So began two years of secret warfare to thwart the manufacture of heavy water.
00:07:46Norwegian commandos blew up the plant.
00:07:49But the Germans had it working again within three months.
00:07:54Then, the US 8th Air Force bombed Vamork.
00:07:59But the heavy water plant survived unscathed.
00:08:06Eventually, in 1944, members of the resistance learned that the entire production plant and 15 tons of partially purified heavy
00:08:15water were to be shipped to Germany.
00:08:18They passed the information on to London, asking what they were to do.
00:08:25The reply was swift.
00:08:27Stop the heavy water reaching Germany.
00:08:35But how?
00:08:36With only days to plan, it fell to Knut and his group to find a way.
00:08:43The plant was closely guarded.
00:08:46But on its journey to Berlin, the heavy water would be transported in barrels down the Rukan Valley by train.
00:08:56It would then travel the length of Lake Tin by ferry.
00:09:05I personally thought that we had to make sure they wouldn't be able to get their hands on this stuff
00:09:10again.
00:09:11And the only place it could be destroyed was Lake Tin.
00:09:15But the saboteurs knew that sinking the ferry would almost certainly mean the death of friends and neighbors.
00:09:22Could a few barrels of water really be that important?
00:09:26They sent a message to London.
00:09:29Doubt whether the effect of the operation is worth the reprisals which must be reckoned on.
00:09:34Stop.
00:09:35As we cannot decide how important the operation is, we request a reply soonest.
00:09:40If possible, this evening.
00:09:43London replied immediately.
00:09:46The matter has been considered, and it is decided that it is very important to destroy the heavy water.
00:09:52Hope it can be done without too great misfortune.
00:09:55Stop.
00:09:56We send our best wishes for success in the work.
00:10:00A message came back that this plan should be carried out.
00:10:04The heavy water destroyed once and for all.
00:10:06Unambiguously put, regardless of the loss of life.
00:10:10So we started the operation.
00:10:17In a 1947 Norwegian film, Knut and his colleagues reenacted their daring mission.
00:10:27We studied drawings of the ferry.
00:10:31At the bottom was a hatchway leading to the bilges.
00:10:41We unscrewed the floor cover to place a time bomb at the bottom of the ferry.
00:10:46The most effective place.
00:10:48While his colleagues planted the bomb, Knut stood guard.
00:10:52Suddenly, they were spotted.
00:10:57There was a guard who asked us what we were doing there.
00:11:02I told him a lie and wondered whether I'd have to kill him.
00:11:10But he felt sorry for us and said he would turn a blind eye if we promised not to tell
00:11:15anyone.
00:11:21He was going off duty at six, and so the guard on the next shift went down with the ferry.
00:11:28So, when he came, he didn't go to the ferry.
00:11:38The next morning, the railway flat cars with their cargo of barrels rolled on board the ferry.
00:11:45Meanwhile, in the hold, the improvised time bomb still ticked away.
00:11:51The hydro was due to sail at 9.30.
00:11:55But at 10 o'clock, it had still not left the dock.
00:12:01The delay meant that Halvard Askild and his fiancée, Solveig Holgen, just got there in time.
00:12:10We were late.
00:12:12We were celebrating my birthday, so we had to run the last bit to get the ferry on time.
00:12:24Finally, the ferry left the dock.
00:12:34We had cake and food from my parents, and we were sitting downstairs in the saloon.
00:12:56Suddenly, there was a bang. The boat was shaking. We thought we'd hit something.
00:13:06The ferry was rapidly filling with smoke and water.
00:13:14Halvard was faced with a terrible dilemma. His fiancée couldn't swim.
00:13:25So, uh...
00:13:26Solveig wanted me to jump.
00:13:29She knew she couldn't swim, but I told her she would have to jump.
00:13:32She said, okay, you first, and I'll follow.
00:13:41I jumped, but she just stayed there and went down with the boat.
00:13:54It's hard for me to talk about this. She was very young. And beautiful.
00:14:00She was very young.
00:14:04She was very young.
00:14:07She was very young.
00:14:09She was very young.
00:14:12Fourteen local people drowned in the icy waters of Lake Tin.
00:14:20But in all other respects, the mission seemed to be a success.
00:14:27The ferry and its cargo sank just where the saboteurs had planned.
00:14:32In the deepest part of the lake, where the Germans could never recover the barrels.
00:14:42I was so elated I'd never run so fast so we could get a message to England.
00:14:50It was as if I had angels' wings.
00:14:53That's how fast I ran just to inform them that the operation had been successful.
00:15:01And the congratulatory telegrams started coming in.
00:15:11But mixed with the congratulations was concerned.
00:15:18Something about the operation didn't seem quite right.
00:15:30The Germans did not seem to feel that there was any reason to protect this shipment.
00:15:36They just sent it on its way.
00:15:38And the chief engineer at Wehmog had also not heard anything about a German guard for this transport.
00:15:47London was suspicious.
00:15:48Had it all been too easy?
00:15:53With regard to the ferry, please make absolutely sure that the barrels on it were not dummy ones,
00:15:59substituted by the Germans.
00:16:01Stop.
00:16:04Did the Germans fool the Norwegian resistance?
00:16:07After the war, it became clear that some barrels containing heavy water
00:16:12had indeed made it to Berlin.
00:16:15What was in those barrels that went down with the hydro?
00:16:19And what was the real significance to the Germans of the heavy water from the morgue?
00:16:25This is one of the last great mysteries of World War II.
00:16:29And there's only one way to solve it.
00:16:35To investigate, marine archaeologist Brett Fanoff has assembled a team to dive to the wreck of the hydro
00:16:43and bring back an intact barrel from its secret cargo.
00:16:47I'm fascinated by World War II, and mostly what I'm fascinated by is that it's within living memory, and yet
00:16:53there's so many discrepancies.
00:16:55And in this case, there are some really glaring inconsistencies in what really was on the hydro.
00:17:00Where was it really headed? Why was it so easy to scuttle?
00:17:05All these things that don't add up, so we want to find out, is it really heavy water?
00:17:10And if it is, was it all of the heavy water? Or is there some heavy water that went somewhere
00:17:14else?
00:17:15And the only way to do that is to go back and look.
00:17:19But it won't be easy.
00:17:21Five tons of special equipment are needed to penetrate one of the world's deepest lakes.
00:17:27So Brett has recruited a Norwegian team with experience in these waters.
00:17:33There's Johnny, who is just a boundless ball of energy. You can't contain him.
00:17:39Always optimistic. So he's been really excited about telling the whole story for Norway.
00:17:43It was touching, you know, a very big part of the history.
00:17:48And suddenly, me and Torvald, small locals, you know, found out that this is the starting of the race for
00:17:57nuclear weapon.
00:17:59And then we've got Tor, who's the typical stoic sort of Norwegian, you know, obviously in charge when you see
00:18:05him out on the lake.
00:18:06And then there's Frederick, who's my partner in crime.
00:18:09We think up the crazy missions together and figure out how to get it all to the field so we
00:18:12can tell these stories.
00:18:14But what was its condition?
00:18:15That was a very good condition.
00:18:16Was it good?
00:18:17Yeah.
00:18:20Perhaps the most important piece of equipment is the team's ROV, or Remotely Operated Vehicle.
00:18:28This is the ROV that we're going to use to look at the ferry.
00:18:32And we have a number of thrusters on it that pushes it forward and up and down in the water.
00:18:37Actually, anybody that plays Nintendo or PlayStation could do it.
00:18:40It's got a very good lighting system on it and a very good camera.
00:18:44We also have a sonar in the front, which helps us navigate and tell us where everything is on the
00:18:49sea floor.
00:18:53From eyewitness reports of the sinking, they have a good idea of where to start looking for the hydro.
00:19:02Tor prepares to dive.
00:19:08It will take about 20 minutes for the ROV to descend to the bottom of Lake Tin.
00:19:23You can see how steep the mountains are, and basically it just continues like that underwater.
00:19:28So we're 300 meters from shore, but it's 400 meters deep.
00:19:33So it's more than a 45-degree slope to depth.
00:19:55A cloud of sediment signals the ROV's safe arrival at the bottom of the lake.
00:20:01There we go.
00:20:06They begin searching the lake bed.
00:20:32Suddenly, the sonar starts to pick up the shape of a hull.
00:20:37This is the solar image of the shipwreck.
00:20:39So it shows us we are about 25 meters away from the ship.
00:20:42So it should come into view on the video screens in a few seconds actually.
00:20:45So we're closing in, as you can see.
00:20:58There we go.
00:20:59Oh, look at that.
00:21:00This is beautiful.
00:21:01It's a big ship.
00:21:08Can you still read the name?
00:21:12Can you see text?
00:21:16Hello.
00:21:18It looks fantastic.
00:21:20It's in great shape.
00:21:22So where are we?
00:21:23Right at the bridge there?
00:21:24Yeah.
00:21:31It's so strange to see a wreck in a lake as opposed to the ocean that's just completely clean.
00:21:36In the ocean, you know, you get so much fuzz on the wreck and there's just nothing on this at
00:21:41all.
00:21:41You see the lantern?
00:21:43Yeah.
00:21:44It's nice.
00:21:4660 years.
00:21:47I think it's still working if you pick it up.
00:21:52The ferry is in remarkable condition, but so far there's no sign of its cargo.
00:21:57The barrels that supposedly held heavy water.
00:22:02If the team does manage to find and salvage one intact, they'll need to analyze its contents.
00:22:08So Brett has asked physicist Dave Wark, an expert in the nuclear properties of heavy water, to join them in
00:22:14Norway.
00:22:17Well, of course, I've known what happened here during the war for many years.
00:22:22The contents of those barrels had a major impact on the course of history.
00:22:28And I'm just fascinated to see what we find when we finally get one up.
00:22:33Before the outbreak of war, the manufacture of heavy water was just a sideline for Norsk Hydro.
00:22:40It came about because to make chemical fertilizer, the company needed hydrogen.
00:22:46And hydrogen could be made from water.
00:22:52Norsk Hydro were using hydroelectricity to make hydrogen.
00:22:56It's actually not a very hard thing to do.
00:22:58If you pass electricity through water, which is H2O, you can break it apart into hydrogen and oxygen.
00:23:08So, as you can see, we're collecting hydrogen here in this test tube, which is basically all that Norsk Hydro
00:23:14were doing, just on a vastly larger scale.
00:23:17And then they'd take the hydrogen and use it to make fertilizer.
00:23:20But a few years before the war, scientists made an extraordinary discovery.
00:23:28A new kind of hydrogen, in which the nucleus contained an extra neutron, making it heavier.
00:23:36They called it deuterium.
00:23:39Just like normal hydrogen, deuterium combined with oxygen to make a new kind of water.
00:23:46Heavy water.
00:23:50We call it heavy water for a very simple reason.
00:23:52I've got some heavy water here that we've frozen into heavy ice.
00:23:56And if I just drop it in this glass of ordinary water, you can see it sinks straight to the
00:24:00bottom.
00:24:02Now, heavy water is actually present in ordinary water.
00:24:06It's about 0.01%.
00:24:08Or in other words, in this five liters of ordinary water, there's about that much heavy water.
00:24:13And one of the side effects of the process of breaking up water into oxygen and hydrogen is the heavy
00:24:21water is very slightly harder to break up than the light water.
00:24:26And so you end up with the water that's left behind having a slightly higher concentration of heavy water.
00:24:32And if you do this again and again and again and again and again and again, you can eventually end
00:24:37up with this, which is essentially pure heavy water.
00:24:40This is from Norsk Hydro.
00:24:42It's 99.76% pure heavy water.
00:24:46It was for this seemingly harmless substance that Norwegian resistance sank the Hydro.
00:24:54That's not a barrel, is it? What is that?
00:24:56It's a pipe.
00:24:57Oh, a stack. Okay.
00:24:59As Tor maneuvers the ROV around the wreck of the Hydro, the team can begin to piece together the last
00:25:06desperate moments of the civilian passengers.
00:25:11Is this the first class section?
00:25:13All right. Okay, it's got four windows, just like on the way here then.
00:25:17We're on the starboard side of the wreck?
00:25:20Yep.
00:25:21Okay.
00:25:21The ceiling have been...
00:25:23Oh, the ceiling's gone.
00:25:25You can see the doors where the people was fighting to get out.
00:25:45Oh, we're right at the...
00:25:47It's the bow.
00:25:48Oh, it's the bow.
00:25:49Oh, it's going down into the setup.
00:25:51Look at that.
00:25:52So the whole forward part of the ship sort of disappears.
00:25:55It's amazing.
00:25:58After the explosion, the ferry sank bow first, and the saloon where Halvard Askild and his fiancée were sitting is
00:26:06now buried in the lake bed.
00:26:09In the confusion, Halvard had left his fiancée for dead.
00:26:15But miraculously, Solvay survived, and witnessed what happened to some of the cargo.
00:26:25I was probably dragged under by the undertow from the boat, and I somehow ended up getting caught in a
00:26:31propeller.
00:26:36I was badly cut and bruised.
00:26:38And the second time I emerged, I managed to grab hold of the life-boy crate.
00:26:51I couldn't see it.
00:26:52I couldn't see a lot, but I did see a barrel next to me, although I have no idea what
00:26:57was in it.
00:26:58A man was trying to get up onto it, but he didn't manage, and he drowned.
00:27:07Eventually, Solvay was picked up by a fishing boat and taken to the same farm as her fiancée Halvard.
00:27:17It's hard to describe such a moment. It's not really possible.
00:27:31Solvay's account confirms that barrels were indeed aboard the hydro.
00:27:35But where are they now? And if they floated, they couldn't have been full of heavy water.
00:27:45Are we very close to the stern now, or is that a rail car there?
00:27:49Oh, that's one of the flat cars. Okay.
00:27:50Boy, that thing is absolutely mangled, though.
00:27:53Yeah.
00:27:53All the wood's gone on it.
00:27:55Or is that the underside we're looking at?
00:27:57Yeah.
00:27:58Ah, I see. Okay, so it's flipped over.
00:28:00We've just seen one of the rail cars. It's sort of flipped upside down and sort of mangled up a
00:28:05little bit.
00:28:07The flat cars should have been loaded with barrels, but everything has been badly crushed.
00:28:17Then, the team gets its first glimpse of the cargo.
00:28:27Here's a barrel, a crashed barrel here.
00:28:33The barrel has been broken open.
00:28:36No one will ever know what it originally contained.
00:28:40But then, a little further on, the ROV reveals more barrels.
00:28:46Two barrels lying on the seafloor.
00:28:51Look at that.
00:28:55Well, that one's wedged under.
00:28:56I wonder how many other got under the wreck when it sank.
00:28:59They don't look in bad shape.
00:29:01Yeah, they seem to be in good shape.
00:29:04The wreck of the Hydro is a Norwegian war grave.
00:29:08Tor decides that these barrels are too close, and decides to back away.
00:29:15It's a very special feeling because you know that it's a lot of people who drowned and the history around
00:29:26it.
00:29:27It's a very...
00:29:29It's a...
00:29:31You have some feelings, yes.
00:29:38Encouraged by finding barrels which seem to have survived the sabotage, the team starts to search the area around the
00:29:45wreck, hoping to find another intact barrel, which might still contain heavy water.
00:29:53But why were the Germans and allies so obsessed with this substance?
00:30:01The answer lies in a discovery based on experiments done in Germany on the eve of the war.
00:30:07A discovery which would have momentous consequences.
00:30:15The story of nuclear energy really starts in 1938 in Berlin, when German physicists found that if you have a
00:30:23uranium nucleus and you hit it with a neutron, you can split it apart or fission it into two smaller
00:30:29nuclei, releasing quite a bit of energy.
00:30:32Now the key point is, in addition to energy, it also releases more neutrons, which can fission more uranium, releasing
00:30:40more neutrons, fissioning more uranium, causing a chain reaction, which in principle can release vast amounts of energy.
00:30:51Now this opened up the very worrying possibility, which was clear to physicists right away, of making nuclear explosives of
00:30:58tremendous power.
00:31:01Hitler's armies were already on the march through Europe.
00:31:05Physicists worldwide suddenly realized there would be a race to develop nuclear weapons.
00:31:11If Germany won it, nothing could stop the Nazis.
00:31:18Professor Mark Walker is an expert in German wartime nuclear research.
00:31:24There certainly was reason for the Allies to have fear about a German nuclear weapons project.
00:31:32Although many excellent scientists fled Hitler's Germany in 1933, Germany still had very good physicists.
00:31:39Among the best was a theoretical physicist, Wanner Heisenberg.
00:31:42He helped create quantum mechanics in the 1920s, won a Nobel Prize for it.
00:31:47Heisenberg was obviously a brilliant scientist.
00:31:50And if nuclear weapons were possible, then he was good enough to get the job done to actually help Germany
00:31:57make a nuclear weapon.
00:32:00With the stage set for World War II, the German military was the first to begin a secret nuclear research
00:32:07program.
00:32:08Recruited along with Heisenberg was his brilliant young protege, Karl Friedrich von Weizsacker.
00:32:15When I first understood that nuclear weapons might be possible, that was in February 1939.
00:32:22Then I felt if such a weapon is possible, there will be somebody who makes it.
00:32:28And if there is somebody who makes it, it will be used.
00:32:31And then I felt this is the most important thing which will happen in my life.
00:32:36And my reaction was, it is true that Hitler will begin a war this year.
00:32:42But Hitler will not persist, but the bomb will be there forever.
00:32:47And therefore, since I am a physicist, and I am able to work in this field,
00:32:54and since I am politically interested, I must in any case enter this field.
00:33:00I cannot keep outside.
00:33:03Working together, Heisenberg and von Weizsacker soon made a crucial discovery.
00:33:09Before the war, scientists had realized that you couldn't make a nuclear bomb from ordinary uranium.
00:33:16But the two German physicists worked out how, in theory, you could turn uranium into the raw material for a
00:33:24bomb.
00:33:27The Germans recognized that natural uranium cannot be used as an explosive.
00:33:32But you can put it in a nuclear reactor.
00:33:35You can have a sustained, controlled, nuclear-efficient chain reaction.
00:33:40And what happens is that the natural uranium, some of it, is transformed into element 94,
00:33:45a transuranic element we now call plutonium.
00:33:48And plutonium is a nuclear explosive.
00:33:50I realized that to make a bomb would be possible with what we now call plutonium, directly,
00:33:58and that plutonium, or agaranium, as I then said, would be produced in reactors by the fact that the reactor
00:34:07works.
00:34:09But to turn these ideas into reality, the Germans needed one vital ingredient, heavy water.
00:34:17In order to make a reactor work, you have to slow the neutrons down by colliding them with something we
00:34:23call a moderator,
00:34:24which slows them down without absorbing them.
00:34:28And it turns out that, in principle, the best moderator is actually heavy water.
00:34:34And the Germans soon realized that if they had enough heavy water as a moderator,
00:34:39they could actually make a reactor work with natural uranium.
00:34:43And from that they could extract plutonium and produce a nuclear explosive.
00:34:48And that's then the link between heavy water, which by itself is harmless, and nuclear explosives.
00:34:56But the Germans were not the only ones to work out a theoretical route to the atom bomb.
00:35:03Scientists in Britain came to the same conclusion.
00:35:06And when America entered the war in December 1941,
00:35:10the two allies pooled their scientific resources in the vast Manhattan Project.
00:35:17People tend to think of the Manhattan Project as a few, you know, physicists on a Mesa in New Mexico.
00:35:25In fact, it had the largest industrial facility ever built in the world.
00:35:29It's a gaseous diffusion plant at Oak Ridge.
00:35:32It included the huge reactor facilities at Hanford, facilities at Berkeley and Chicago.
00:35:37And it was bigger than the US auto industry at the time.
00:35:41It's been a huge amount of money.
00:35:43It was really an enormous effort.
00:35:47Allied scientists knew all their work would be in vain if the Germans got there first.
00:35:55But German progress depended on a steady supply of heavy water,
00:36:00which British intelligence and the Norwegian resistance were determined they would not get.
00:36:10They would not get there.
00:36:11At the dive site, the team has finally met with success.
00:36:15They've sighted several barrels, including one that looks intact.
00:36:19They're getting ready to lift it as physicist Dave Wark arrives.
00:36:23Hi, I'm Dave.
00:36:24Brent, how are you?
00:36:25Hello, pleased to meet you.
00:36:28We have found nine barrels so far.
00:36:30One on the ship and then eight on the lake floor around the ship.
00:36:34Two very close to the shipwreck.
00:36:36And we have selected the one that looks the best.
00:36:39That's about 60 meters away from the shipwreck itself.
00:36:42And it looks complete and we hope that it will contain heavy water.
00:36:46So we're heading for that one now.
00:36:51On the lake bed, the ROV inches toward the target.
00:36:57Yes, it's a barrel. It's the end of it.
00:36:59Oh, yeah. That's the barrel.
00:37:01Yes.
00:37:02Do you read anything on the end?
00:37:05Upside down five?
00:37:07I don't know.
00:37:08It could be.
00:37:10To lift the barrel, a specially designed grapple has been attached to one of the ROVs.
00:37:17Tor has to position it in exactly the right place over the rim.
00:37:21This is just once.
00:37:23You get one try?
00:37:24Yes, only one try.
00:37:26Okay.
00:37:28Cross your fingers.
00:37:30Yes, we do.
00:37:32Contact.
00:37:37There is it.
00:37:40It slipped off.
00:37:42Yeah.
00:37:43You have enough tether out.
00:37:46Slap and tether.
00:37:49Oh, there.
00:37:53It's tight there.
00:37:55It's tight there.
00:37:56The next delicate step is to let go of the grapple.
00:38:03There, there.
00:38:04And we're off.
00:38:06Okay, and then the connector is hanging.
00:38:08You can see the connector hanging there.
00:38:09So we have to pull out that one too.
00:38:12Oh, it's pointed out.
00:38:13There we go.
00:38:13This is the point of no return.
00:38:15Over there.
00:38:16Now it either comes or it doesn't.
00:38:17Pull it up.
00:38:18Yeah.
00:38:21The barrel is buried deep in the mud.
00:38:24They'll have to pull very hard to get it out.
00:38:30I know.
00:38:32It's great.
00:38:33It weighs over two tons.
00:38:35So it should go well.
00:38:36They're just discussing if the rope will take attention or not.
00:38:39Yeah.
00:38:40Is it now a bad time to worry about that?
00:38:43That's what he's saying.
00:38:44It's no problem.
00:38:45Pull, pull, go on and pull.
00:38:47That's what he's saying.
00:38:48Okay.
00:38:49They're pulling.
00:38:56No sign of any movement yet.
00:38:58No.
00:39:01Can they tell how much force they're putting onto that winch?
00:39:04No, not exactly.
00:39:06Suddenly it will just...
00:39:07Go.
00:39:08Pop free.
00:39:08Yeah, it will pop free.
00:39:09So it's...
00:39:10Hard to say exactly when it's gonna happen.
00:39:13How far do you feel?
00:39:15There's a slight movement in it, so...
00:39:19Okay.
00:39:20It's coming, it's coming.
00:39:21It's coming, it's coming.
00:39:27Okay.
00:39:27Boom.
00:39:28Goodbye.
00:39:30Barrel on a bungee.
00:39:32And did you see the bottom of the barrel when it came out?
00:39:34Oh, yeah.
00:39:34The paint was still on it.
00:39:36Yep.
00:39:37Amen.
00:39:41Don't drop it.
00:39:46The underwater cameras on the ROV provide the first close look at the barrel in 60 years.
00:39:52It appears intact, but the smallest of holes is enough to contaminate any heavy water it may contain with lake
00:40:00water.
00:40:01Luckily, the process of electrolysis, which concentrated the heavy water, should have left traces, which will allow Dave to test
00:40:09for contamination.
00:40:12The barrels contain heavy water, we hope, but to make the heavy water, to separate it originally, they had to
00:40:18add something else to make the water conduct electricity.
00:40:21They added something called potash lye, which is actually potassium hydroxide, which will make the water very caustic.
00:40:27Now, we measure whether our water is caustic or not on a scale called pH.
00:40:33Well, now we're going to want to know whether the pH in the barrel is different than the pH of
00:40:38the lake water, so I have to know what the pH of the lake water is.
00:40:41So now I'm going to test it and find out.
00:40:45Okay.
00:40:46Now you can see it's about 9, which is a little higher than you expect for ordinary water, but still
00:40:51much less than you would expect for the material in the barrel, which should have a pH of about 14.
00:40:57So when we open up a barrel, if it's 14, it's probably uncontaminated. If it's 9, it's just lake water.
00:41:31We have a barrel in very good shape, I think.
00:41:36We have secured the barrel with two straps because we couldn't lift it out of the water with this hook
00:41:42that we put on it. That would be too much stress on the barrel.
00:41:45It's still going to be quite a bit of stress on the barrel as we lift it through the waterfall.
00:41:50Take that very, very slowly and make sure it doesn't bump it and things like that.
00:41:57It was absolutely fascinating to actually see that barrel come up.
00:42:01You think of the Second World War as something that happens in grainy old movies from your dad's era.
00:42:07You don't think of it as something immediate and to see the actual barrel come up out of the water
00:42:13is an amazing experience.
00:42:17But can you see the number here now that we see here? Yes, it's 26.
00:42:26No, it's perfect. The corrosion goes at one angle and the dirt goes at another and there's a little clear
00:42:32sector left and the 26 is right in the middle of it like it was planned that way.
00:42:38But you know, nothing is pouring out and it's full of something.
00:42:43Well, we've got the barrel and we can clearly read the number on the end of it, which is fantastic.
00:42:49It's barrel number 26.
00:42:51So the question is, have the contents of the barrel been contaminated with lake water?
00:42:58Oh, it's coming. Oh, we're drinking.
00:43:01It's coming up, Dave.
00:43:03Yeah, just go very slowly. Let it release the pressure.
00:43:07I think it's amazing. It comes up and it takes off the lid.
00:43:11Yes, it takes off the lid, yes.
00:43:13The gasket is good still, you know.
00:43:16Yeah, they built him good back then.
00:43:19Oh, look here. Very good.
00:43:21Look here. It's been boiling. Be careful here.
00:43:24Careful, careful, careful.
00:43:27Precautions are being taken here. Potassium hydroxide is very, very costly.
00:43:32It looks clear.
00:43:35There it is.
00:43:37This, I think, is good stuff, Dave.
00:43:39Yeah, it looks good.
00:43:40It's not like water, you know. It's a bit more softer of the viscosity.
00:43:45I'm now going to measure the pH.
00:43:47Just put this meter in the solution and wait a few moments for it to equilibrate.
00:43:59It's good stuff.
00:44:01Fourteen, that's your guess, wasn't it?
00:44:03Fourteen. You're satisfied?
00:44:05Yes!
00:44:05Yes!
00:44:07Very good.
00:44:08Sixty years.
00:44:09Sixty years.
00:44:10It's exactly the way it was the day they put it in there.
00:44:13I will be damned.
00:44:14Yes, you will.
00:44:15Okay.
00:44:17Shake hands with this.
00:44:18And also get a kiss now.
00:44:22Fantastic.
00:44:24They sank it and believed it should never come to the surface again.
00:44:28Everybody said, it's gone forever.
00:44:30But after sixty years, it's still low, you know.
00:44:35Well, I mean, it's an incredible feeling.
00:44:37There was a heck of a lot of work to get this.
00:44:39So, we have to get this back to the lab in London,
00:44:43so we can find out what the purity of the heavy water really is.
00:44:48Because, amazingly, the number of the barrel is still legible.
00:44:52Dave will be able to do far more than just check if it contains heavy water.
00:44:57In the archives of Norsk Hydro, Per Dahl has found documents describing the entire shipment aboard the Hydro when it
00:45:05sank.
00:45:07Here is a list of the various barrels transported on the Hydro ferry
00:45:13and the amount of heavy water in each of those barrels in various concentrations.
00:45:20According to this manifest, the concentration of heavy water in barrel 26 was just 1%.
00:45:28To detect such a low concentration will require careful analysis.
00:45:33At Imperial College London, Dave and his colleagues compare the infrared spectrum of the water molecules from the barrel
00:45:42with the spectra from samples of different known concentrations of heavy water.
00:45:46We've tested the samples of heavy water here at Imperial quite a few times,
00:45:51and we can say with considerable confidence that that water is enriched in heavy water.
00:45:58The result is unequivocal.
00:46:05It's about 1.1% plus or minus 0.2% heavy water,
00:46:10which, interestingly, is pretty much exactly what the manifest said it would be.
00:46:16So one mystery about the Hydro has been forever laid to rest.
00:46:22We've learned there really was heavy water on the Hydro.
00:46:24Any speculations that the Germans had pulled some sort of swap are just not true.
00:46:28The shipping manifest appears to be largely correct.
00:46:32And that helps to clear up another puzzle.
00:46:35The manifest shows that the low numbered barrels which contained the high concentration heavy water
00:46:41were little more than half full.
00:46:44That explains why some of them floated.
00:46:47It was probably these barrels recovered by the Germans which ended up in Berlin as reports after the war suggested.
00:46:54But it also raises a troubling question.
00:46:57It's clear from the manifest that most of the barrels contained only very dilute heavy water.
00:47:03Despite the apparent size of the shipment, the total quantity of pure heavy water was quite small.
00:47:12The Germans would have needed a total of about 5 tons of heavy water to get a heavy water reactor,
00:47:19nuclear reactor, running.
00:47:22The list here informs us essentially that about half a ton of heavy water was being transported to Germany.
00:47:34The Hydro was carrying far too little heavy water for even one reactor,
00:47:39let alone the 10 or more that would have been needed to make enough plutonium for a nuclear weapon.
00:47:45So were the Allies right in their belief that the heavy water was destined for a bomb project?
00:47:52Did the Germans in fact want it for some other purpose?
00:48:00Within a few months of the sinking of the Hydro in 1944, Allied armies were advancing across Europe.
00:48:07Following closely behind the frontline troops was a secret operation codenamed ALSOS.
00:48:15Its mission was to find the Nazi nuclear weapons program the Allies were sure must exist.
00:48:22For months, ALSOS scoured newly liberated Europe and found nothing.
00:48:28Then, just days before the final German surrender, they came to Heigerloch, a small town in Bavaria.
00:48:37Beneath a church there was a cave.
00:48:39And inside they found the intended destination of the Norwegian heavy water.
00:48:45A makeshift laboratory with a small experimental reactor that German scientists still had not gotten to work.
00:48:54The Nazi nuclear bomb, which had inspired so much fear, turned out to be a mirage.
00:49:02There was no German equivalent of the vast Manhattan Project.
00:49:08The reason, believes historian Mark Walker, can be found in a decision made in early 1942,
00:49:16just at the time when the Allies were also deciding whether to embark on the Manhattan Project.
00:49:23In early 1942, precisely when the Allies were getting concerned about Norwegian heavy water,
00:49:28American officials and German officials made crucial decisions about their nuclear weapons projects.
00:49:34Interestingly, scientists in both countries said the same thing.
00:49:38The scientific results were essentially the same.
00:49:41Scientists in both countries said,
00:49:42it'll take a couple years, but nuclear weapons are possible.
00:49:46Now, in America, it was assumed that the war is going to take a long time.
00:49:51These weapons would be done before the end of the war.
00:49:54Therefore, we have to try to make them.
00:49:57In Germany, it was assumed that if we don't win the war quickly, we will lose.
00:50:02These weapons might be interesting for the future, but they're no help to us now.
00:50:07It would be a waste of energy, money and time to try to make them.
00:50:13So German nuclear research was transferred to civilian control.
00:50:18The hydro shipment was destined for an experimental reactor project.
00:50:23It was of no military significance, which is why it was only lightly guarded.
00:50:31So it seems that the doubts the Norwegian resistance expressed about the value of sinking the hydro were justified.
00:50:39Had Allied intelligence known what we know today,
00:50:43they might well have agreed that the shipment was not worth stopping.
00:50:49I would say that the Allies were not paranoid as such.
00:50:55Rather, they were surprisingly uninformed about what was going on in Germany in nuclear physics.
00:51:02The German program was very leaky.
00:51:05They were telling journalists in cafes what they were up to.
00:51:09And yet, the Allies don't seem to have made much of an effort to really penetrate this program and learn
00:51:15more about it.
00:51:17I would call that a critical intelligence failure.
00:51:23None of this, of course, takes away from the heroism of Knut Lear Hansen and his comrades.
00:51:31They chose to take up arms against a brutal invader at great risk to themselves.
00:51:38They knew their actions would lead to the death of innocent civilians.
00:51:45But the bitter truth is that World War II, like most modern wars, claimed mainly the lives of the innocent.
00:52:05They asked London. London said immediately, sink it.
00:52:08And they did what they were told.
00:52:09It would be like asking me to blow up the 845 train to London.
00:52:13And we would be absolutely certain there would be friends, maybe even relatives of mine on that train.
00:52:17But if there's any chance that Hitler is going to get an atomic bomb, what else can you do?
00:52:23I think you have to look at it and get it all straight for once and for all, for everybody,
00:52:29for the history books,
00:52:30and not worry about who might be offended.
00:52:35Because it's not about that. It's not about criticizing what they did.
00:52:37I would have done it if I had been given the orders. I'd like to think that I'd follow the
00:52:40orders.
00:52:41I don't think I would have had the guts to do what they did.
00:52:44No, they were special guys though.
00:53:00Stay tuned for a new season of This Old House, coming up next.
00:53:15To order this show or any other NOVA program for $19.95 plus shipping and handling,
00:53:22call WGBH Boston Video at 1-800-255-9424.
00:53:41NOVA is a production of WGBH Boston.
00:53:44We also have a sonar in the front which helps us navigate and tell us where everything is on the
00:53:49sea floor.
00:53:53From eyewitness reports of the sinking, they have a good idea of where to start looking for the hydro.
00:54:02Tor prepares to dive.
00:54:08It will take about 20 minutes for the ROV to descend to the bottom of Lake Tin.
00:54:23You can see how steep the mountains are, and basically it just continues like that underwater.
00:54:28So we're 300 meters from shore, but it's 400 meters deep.
00:54:33So it's more than a 45-degree slope to depth.
00:54:55There we go.
00:54:56A cloud of sediment signals the ROV's safe arrival at the bottom of the lake.
00:55:01There we go.
00:55:06They begin searching the lake bed.
00:55:32Suddenly, the sonar starts to pick up the shape of a hull.
00:55:37This is the solar image of the shipwreck.
00:55:39So it shows us we are about 25 meters away from the ship.
00:55:42So it should come into view on the video screens in a few seconds, actually.
00:55:45We're closing in, as you can see.
00:55:58There we go.
00:55:59Oh, look at that. This is beautiful.
00:56:01It's a big ship.
00:56:08Can you still read the name?
00:56:12Can you see text?
00:56:16Hello.
00:56:18It looks fantastic. It's in great shape.
00:56:22So where are we? Right at the bridge there?
00:56:24Yeah.
00:56:31It's so strange to see a wreck in a lake as opposed to the ocean that's just completely clean.
00:56:36In the ocean, you know, you get so much fuzz on the wreck and there's just nothing on this at
00:56:41all.
00:56:42See the lantern?
00:56:43Yeah.
00:56:44Hard to describe such a moment.
00:56:47It's not really possible.
00:56:49going calm.
00:56:58Solvay's account confirms that barrels were indeed aboard the hydro.
00:57:02But where are they now?
00:57:04And if they floated, they couldn't have been full of heavy water.
00:57:12Are we very close to the stern now?
00:57:14Or is that a rail car there?
00:57:16Yeah.
00:57:16Oh, that's one of the flat cars.
00:57:17Okay.
00:57:17Boy, that thing is absolutely mangled, though.
00:57:20Yeah.
00:57:20All the wood's gone on it.
00:57:22Or is that the underside we're looking at?
00:57:24Yeah.
00:57:25I see. Okay.
00:57:26So it's flipped over.
00:57:27We've just seen one of the rail cars.
00:57:29It's sort of flipped upside down and sort of mangled up a little bit.
00:57:34The flat cars should have been loaded with barrels.
00:57:38But everything has been badly crushed.
00:57:44Then, the team gets its first glimpse of the cargo.
00:57:54Here's a barrel, crashed barrel here.
00:58:00The barrel has been broken open.
00:58:03No one will ever know what it originally contained.
00:58:07But then, a little further on, the ROV reveals more barrels.
00:58:13Two barrels lying on the seafloor.
00:58:18Look at that.
00:58:22Well, that one's wedged under.
00:58:23I wonder how many other got under the wreck when it sank.
00:58:26They don't look in bad shape.
00:58:28Yeah, they seem to be in good shape.
00:58:31The wreck of the Hydro is a Norwegian war grave.
00:58:35Tor decides that these barrels are too close and decides to back away.
00:58:42It's a very special feeling because you know that it's a lot of people who drowned and the history around
00:58:53it.
00:58:55It's a very...
00:58:57It's a...
00:58:58You have some feelings, yes.
00:59:04Encouraged by finding barrels which seem to have survived the sabotage, the team starts to search the area around the
00:59:12wreck, hoping to find another intact barrel which might still contain heavy water.
00:59:20But why were the Germans and allies so obsessed with this substance?
00:59:28The answer lies in a discovery based on experiments done in Germany on the eve of the war.
00:59:34A discovery which would have momentous consequences.
00:59:42The story of nuclear energy controlled nuclear efficient chain reaction.
00:59:46And what happens is that the natural uranium, some of it is transformed into element 94, a transuranic element we
00:59:53now call plutonium.
00:59:54And plutonium is a nuclear explosive.
00:59:56I realized that to make a bomb would be possible with what we now call plutonium directly and that plutonium
01:00:06or agaranium as I then said would be produced in reactors by the fact that the reactor works.
01:00:14But to turn these ideas into reality, the Germans needed one vital ingredient, heavy water.
01:00:23In order to make a reactor work, you have to slow the neutrons down by colliding them with something we
01:00:29call a moderator, which slows them down without absorbing them.
01:00:34And it turns out that in principle, the best moderator is actually heavy water.
01:00:40And the Germans soon realized that if they had enough heavy water as a moderator, they could actually make a
01:00:46reactor work with natural uranium.
01:00:48And from that they could extract plutonium and produce a nuclear explosive.
01:00:54And that's then the link between heavy water, which by itself is harmless, and nuclear explosives.
01:01:02But the Germans were not the only ones to work out a theoretical route to the atom bomb.
01:01:09Scientists in Britain came to the same conclusion.
01:01:11And when America entered the war in December 1941, the two allies pooled their scientific resources in the vast Manhattan
01:01:21Project.
01:01:23People tend to think of the Manhattan Project as a few, you know, physicists on a mesa in New Mexico.
01:01:30In fact, it had the largest industrial facility ever built in the world.
01:01:35It's a gaseous diffusion plant at Oak Ridge.
01:01:38It included the huge reactor facilities at Hanford, facilities at Berkeley and Chicago.
01:01:44And it was bigger than the U.S. auto industry of the time.
01:01:47It spent a huge amount of money.
01:01:49It was really an enormous effort.
01:01:53Allied scientists knew all their work would be in vain if the Germans got there first.
01:02:01But German progress depended on a steady supply of heavy water,
01:02:06which British intelligence and the Norwegian resistance were determined they would not get.
01:02:16At the dive site, the team has finally met with success.
01:02:21They've sighted several barrels, including one that looks intact.
01:02:25They're getting ready to lift it as physicist Dave Warke arrives.
01:02:29Hi, I'm Dave.
01:02:30Brent, how are you?
01:02:31Hello.
01:02:32Please meet you.
01:02:34We have found nine barrels so far.
01:02:36One on the ship and then eight on the lake floor around the ship.
01:02:40Two very close to the shipwreck.
01:02:43And we have selected...
01:02:44An army will begin a top secret research program to develop nuclear weapons.
01:02:52It is based on experiments performed in Berlin that showed for the first time that the atom can be split,
01:02:59unleashing immense power.
01:03:07German scientists were the first to start work on the atom bomb.
01:03:12But they would never finish the job.
01:03:17Just why has always been a mystery.
01:03:24In search of clues to solve this mystery, a team of underwater archaeologists has come to this lake in Norway.
01:03:33They're looking for the cargo that was on board this sunken ferry.
01:03:39Look at that.
01:03:41There's something there, isn't there?
01:03:43Is the key to the Nazi nuclear bomb about to emerge from the icy depths of a Norwegian lake?
01:03:52Hitler's sunken secret, right now on NOVA.
01:04:17For sixty years, the icy waters of Norway's Lake Tin have held a secret.
01:04:28Today, its peaceful shores show little sign of the conflict that raged here in World War II.
01:04:41But under Nazi occupation, this region witnessed a deadly underground war of spies and saboteurs.
01:04:50The battle was for one thing above all, a mysterious substance called heavy water that the Norwegian resistance fought desperately
01:05:01to keep out of German hands.
01:05:06In 1944, in a daring act of sabotage, a passenger ferry carrying several barrels of heavy water was sent to
01:05:17the bottom of Lake Tin.
01:05:22Now a team of underwater archaeologists is looking for those barrels.
01:05:30They want to know what's really inside them.
01:05:35Because they may contain the key to the only weapon that could have won the war for Hitler.
01:05:40A Nazi nuclear bomb would then travel the length of Lake Tin by ferry.
01:05:52I personally thought that we had to make sure they wouldn't be able to get their hands on this stuff
01:05:57again.
01:05:57And the only place it could be destroyed was Lake Tin.
01:06:02But the saboteurs knew that sinking the ferry would almost certainly mean the death of friends and neighbors.
01:06:09Could a few barrels of water really be that important?
01:06:13They sent a message to London.
01:06:30London replied immediately.
01:06:33The matter has been considered and it is decided that it is very important to destroy the heavy water.
01:06:39Stop.
01:06:39Hope it can be done without too great misfortune.
01:06:43Stop.
01:06:43We sent our best wishes for success in the work.
01:06:47A message came back that this plan should be carried out.
01:06:51The heavy water destroyed once and for all.
01:06:53Unambiguously put, regardless of the loss of life.
01:06:57So we started the operation.
01:07:05In a 1947 Norwegian film, Knut and his colleagues reenacted their daring mission.
01:07:14We studied drawings of the ferry.
01:07:18At the bottom was a hatchway leading to the bilges.
01:07:28We unscrewed the floor cover to place a time bomb at the bottom of the ferry.
01:07:35While his colleagues planted the bomb, Knut stood guard.
01:07:39Suddenly, they were spotted.
01:07:44There was a guard who asked us what we were doing there.
01:07:49I told him a lie and wondered whether I'd have to kill him.
01:07:57But he felt sorry for us and said he would turn a blind eye if we promised not to tell
01:08:01anyone.
01:08:08He was going off duty at six and so the guard on the next shift went down with the ferry.
01:08:25The next morning, the railway flat cars with their cargo of barrels rolled on board the ferry.
01:08:32Meanwhile, in the hold, the improvised time bomb still ticked away.
01:08:38The hydro was due to sail at 9.30.
01:08:42But at 10 o'clock, hydrogen and hydrogen could be made from water.
01:08:50Norsk Hydro were using hydroelectricity to make hydrogen.
01:08:54It's actually not a very hard thing to do.
01:08:56If you pass electricity through water, which is H2O, you can break it apart into hydrogen and oxygen.
01:09:06So, as you can see, we're collecting hydrogen here in this test tube,
01:09:10which is basically all that Norsk Hydro were doing, just on a vastly larger scale.
01:09:15And then they'd take the hydrogen and use it to make fertilizer.
01:09:18But a few years before the war, scientists made an extraordinary discovery.
01:09:26A new kind of hydrogen, in which the nucleus contained an extra neutron, making it heavier.
01:09:34They called it deuterium.
01:09:37Just like normal hydrogen, deuterium combined with oxygen to make a new kind of water.
01:09:44Heavy water.
01:09:48We call it heavy water for a very simple reason.
01:09:50I've got some heavy water here that we've frozen into heavy ice.
01:09:54And if I just drop it in this glass of ordinary water, you can see it sinks straight to the
01:09:58bottom.
01:10:00Now, heavy water is actually present in ordinary water.
01:10:04It's about 0.01%.
01:10:06Or in other words, in this five liters of ordinary water, there's about that much heavy water.
01:10:11And one of the side effects of the process of breaking up water into oxygen and hydrogen
01:10:18is the heavy water is very slightly harder to break up than the light water.
01:10:24And so you end up with the water that's left behind having a slightly higher concentration of heavy water.
01:10:30And if you do this again and again and again and again and again and again and again,
01:10:34you can eventually end up with this, which is essentially pure heavy water.
01:10:38This is from Norsk Hydro.
01:10:40It's 99.76% pure heavy water.
01:10:44It was for this seemingly harmless substance that Norwegian resistance sank the Hydro.
01:10:52That's not a barrel, is it? What is that?
01:10:54It's a pipe.
01:10:55Oh, a stack, okay.
01:10:57As Tor maneuvers the ROV around the wreck of the Hydro,
01:11:01the team can begin to piece together the last desperate moments of the civilian passengers.
01:11:08Wait, this is the first class section.
01:11:11All right, okay, it's got four windows, just like on the...
01:11:14So we're here then?
01:11:15We're on the starboard side of the wreck?
01:11:18Yep.
01:11:19Okay.
01:11:19The ceiling have been...
01:11:21Oh, the ceiling's gone.
01:11:23You can see the doors where the people was fighting to get out.
01:11:43That the Norwegian resistance fought desperately to keep out of German hands.
01:11:51In 1944, in a daring act of sabotage, a passenger ferry carrying several barrels of heavy water was sent to
01:12:02the bottom of Lake Tin.
01:12:07Now a team of underwater archaeologists is looking for those barrels.
01:12:14They want to know what's really inside them.
01:12:20Because they may contain the key to the only weapon that could have won the war for Hitler.
01:12:25A Nazi nuclear bomb.
01:12:40The story begins on April 9th, 1940, when Nazi Germany invaded the small, neutral country of Norway.
01:12:52Taken by surprise and betrayed by Nazi sympathizers in their own government, the Norwegians could offer little resistance.
01:13:04As opposition crumbled, the Germans headed straight for the remote area around Lake Tin to take control of Norway's most
01:13:12valuable industrial enterprise.
01:13:16High in the mountains, at the head of the Rukan Valley, was the Bamork hydroelectric plant, once the world's largest
01:13:24power station.
01:13:28The Norsk Hydro Company used that power to make ammonia, the basis of fertilizer and explosives, both vital to the
01:13:36German war effort.
01:13:41But inside the Norsk Hydro plant was a room of specialized equipment that made something even more valuable.
01:13:53Where are we here then?
01:13:55Well, look here, the original stuff, the high concentration cells.
01:14:00Physicist and historian Per Dahl is an expert on what happened here during World War II.
01:14:06We are really looking here at the piece of history, the original high concentration cells for producing heavy water.
01:14:15Heavy water was a strange new form of water that had only recently been discovered.
01:14:22And Norsk Hydro was making small quantities to supply scientists around the world who were investigating its properties.
01:14:34As soon as they took over the plant, the Germans set about increasing production.
01:14:40They doubled the production apparatus, expand.
01:14:44Have the contents of the barrel been contaminated with lake water?
01:14:49Oh, it's coming!
01:14:51Oh, we're drinking now!
01:14:52It's coming up, Dave!
01:14:53Yeah, just go very slowly, let it release the pressure.
01:14:58I think it's amazing, it comes up and you take off the lid!
01:15:01Yes, you take up and take off the lid, yes!
01:15:04The gasket is good still, you know?
01:15:07Yeah, they built them good back then.
01:15:10Oh, look here!
01:15:11Very good!
01:15:12Look here!
01:15:13It's still boiling!
01:15:14Be careful here!
01:15:15Careful, careful, careful!
01:15:18Precautions are being taken here.
01:15:20Potassium hydroxide is very, very caustic.
01:15:23It looks clear!
01:15:26There it is!
01:15:27This, I think, is good stuff, Dave.
01:15:30Yeah, it looks good!
01:15:31It's not like water, you know, it's a bit more softer of viscosity.
01:15:36I'm now going to measure the pH.
01:15:38Just put this meter in the solution and wait a few moments for it to equilibrate.
01:15:50It's good stuff!
01:15:52Fourteen, that's your guess, wasn't it?
01:15:54Fourteen!
01:15:54You satisfied?
01:15:55Yeah!
01:15:56Yes!
01:15:58Very good!
01:15:59Sixty years!
01:16:00Sixty years!
01:16:01It's exactly the way it was the day they put it in there.
01:16:04I will be damned.
01:16:05Yes, you will.
01:16:06Okay, shake hands with this.
01:16:09I'd also get a kiss now.
01:16:13Fantastic!
01:16:15They sank it and believed it should never come to the surface again.
01:16:19Everybody said, it's gone forever.
01:16:21But after sixty years, it's still there, you know?
01:16:25Well, I mean, it's an incredible feeling.
01:16:28It was a heck of a lot of work to get this.
01:16:30So we have to get this back to the lab in London so we can find out what the purity
01:16:36of the heavy water really is.
01:16:38Because, amazingly, the number of the barrel is still legible, Dave will be able to do far more than just
01:16:46check if it contains heavy water.
01:16:48In the archives of Norsk Hydro, Per Dahl has found documents describing the entire shipment aboard the hydro when it
01:16:56sank.
01:16:57Here is a list of the various barrels transported on the hydro ferry and the amount of heavy water in
01:17:07each of those barrels in various concentrations.
01:17:11According to this manifest, the concentration of heavy water in barrel 26 was just one percent.
01:17:19To detect such a low concentration will require careful analysis.
01:17:23At Imperial College London, Dave and his colleagues compare the infrared spectrum of the water molecules from the barrel with
01:17:33the spectra from samples of different known concentrations of heavy water.
01:17:37We've tested the samples of heavy water here at Imperial quite a few times, and we can say we've...
01:17:45The delay meant that Halvard Askild and his fiancée, Solveig Holgen, just got there in time.
01:17:54We were late. We were celebrating my birthday, so we had to run the last bit to get the ferry
01:18:01on time.
01:18:09Finally, the ferry left the dock.
01:18:19We had cake and food from my parents, and we were sitting downstairs in the saloon.
01:18:41Suddenly, there was a bang. The boat was shaking. We thought we'd hit something.
01:18:51The ferry was rapidly filling with smoke and water.
01:18:59Halvard was faced with a terrible dilemma. His fiancée couldn't swim.
01:19:11Solveig wanted me to jump.
01:19:14She knew she couldn't swim, but I told her she would have to jump.
01:19:17She said, OK, you first, and I'll follow.
01:19:26I jumped, but she just stayed there and went down with the boat.
01:19:39It's hard for me to talk about this. She was very young and beautiful.
01:19:45She was very young and beautiful.
01:19:57Fourteen local people drowned in the icy waters of Lake Tin.
01:20:05But in all other respects, the mission seemed to be a success.
01:20:12The ferry and its cargo sank just where the saboteurs had planned,
01:20:17in the deepest part of the lake, where the Germans could never recover the barrels.
01:20:27I was so elated. I'd never run so fast so we could get a message to England.
01:20:35It was as if I had angels' wings. That's how fast I ran, just to inform them that the operation
01:20:42had been successful.
01:20:47I was badly cut and bruised. And the second time I emerged, I managed to grab hold of the Lifebuoy
01:20:54crate.
01:21:02I couldn't see a lot, but I did see a barrel next to me, although I have no idea what
01:21:08was in it.
01:21:08A man was trying to get up onto it, but he didn't manage, and he drowned.
01:21:18Eventually, Solvay was picked up by a fishing boat, and taken to the same farm as her fiancé, Halvard.
01:21:28Hard to describe such a moment. It's not really possible.
01:21:33Go and come.
01:21:42Solvay's account confirms that barrels were indeed aboard the Hydro.
01:21:46But where are they now?
01:21:48And if they floated, they couldn't have been full of heavy water.
01:21:56Are we very close to the stern now? Or is that a rail car there?
01:22:00Oh, that's one of the flat cars. Okay.
01:22:01Boy, that thing is absolutely mangled, though.
01:22:04Yeah.
01:22:04All the wood's gone on it.
01:22:06Or is that the underside we're looking at?
01:22:08Yeah.
01:22:09I see, okay. So it's flipped over.
01:22:11We've just seen one of the rail cars, sort of flipped upside down, and sort of mangled up a little
01:22:16bit.
01:22:16Yeah.
01:22:18The flat cars should have been loaded with barrels, but everything has been badly crushed.
01:22:28Then, the team gets its first glimpse of the cargo.
01:22:38Here's a barrel, a crashed barrel here.
01:22:44The barrel has been broken open.
01:22:47No one will ever know what it originally contained.
01:22:51But then, a little further on, the ROV reveals more barrels.
01:22:57Two barrels lying on the seafloor.
01:23:02Look at that.
01:23:05Well, that one's wedged under.
01:23:07I wonder how many other got under the wreck when it sank.
01:23:10They don't look in bad shape.
01:23:12Yeah, they seem to be in good shape.
01:23:15The wreck of the Hydro is a Norwegian war grave.
01:23:18Tor decides that these barrels are too close, and decides to back away.
01:23:26That's a very special feeling, because you know that it's a lot of people who drowned, and the history around
01:23:37it.
01:23:38It's a very, it's a, you have some feelings.
01:23:44The water conduct electricity.
01:23:45They added something called potash lye, which is actually potassium hydroxide, which will make the water very caustic.
01:23:52Now, we measure whether water is caustic or not on a scale called pH.
01:23:57Well, now, we're going to want to know whether the pH in the barrel is different than the pH of
01:24:02the lake water.
01:24:03So, I have to know what the pH of the lake water is.
01:24:05So, now I'm going to test it and find out.
01:24:09Okay.
01:24:10Now, you can see it's about nine, which is a little higher than you expect for ordinary water.
01:24:15But still, much less than you would expect for the material in the barrel, which should have a pH of
01:24:20about 14.
01:24:21So, when we open up a barrel, if it's 14, it's probably uncontaminated.
01:24:26If it's nine, it's just lake water.
01:24:55I have a barrel in very good shape, I think.
01:25:00We have secured the barrel with two straps because we couldn't lift it out of the water with this hook
01:25:06that we put on it.
01:25:07That would be too much stress on the barrel.
01:25:09It's still going to be quite a bit of stress on the barrel as we lift it through the water
01:25:13hole.
01:25:13Take that very, very slowly, make sure it doesn't bump it and things like that.
01:25:21It was absolutely fascinating to actually see that barrel come up.
01:25:25You think of the Second World War as something that happens in grainy old movies from your dad's era.
01:25:31You don't think of it as something immediate.
01:25:34And to see the actual barrel come up out of the water is an amazing experience.
01:25:41But can you see the number here now?
01:25:43Can we see here?
01:25:48Yes, it's 26.
01:25:50No, it's perfect. The corrosion goes at one angle and the dirt goes at another and there's a little clear
01:25:56sector left.
01:25:57And the 26 is right in the middle of it, like it was planned that way.
01:26:02But you know, nothing is pouring out and it's full of something.
01:26:06Well, we've got the barrel and we can clearly read the number on the end of it, which is fantastic.
01:26:12It's barrel number 26.
01:26:15So the question is, have the contents of the barrel been contaminated with lake water?
01:26:22Oh, it's coming.
01:26:24Oh, it's coming up.
01:26:25It's coming up, Dave.
01:26:26Yeah, just go very slowly. Let it release the pressure.
01:26:31I think it's amazing. It comes up and you take off the lid.
01:26:34Yes, you take off and take off the lid, yes.
01:26:37The gasket is good still, you know.
01:26:40Yeah, they built him good back then.
01:26:42Okay. All right.
01:26:51The next delicate step is to let go of the grapple.
01:26:58There, there, and we're off.
01:27:02Okay, and then the connector is hanging. You can see the connector hanging there, so we have to pull out
01:27:07that one too.
01:27:08And we're off. This is the point of no return. No way there.
01:27:11Yeah. No, it either comes or it doesn't.
01:27:13When you pull it up?
01:27:14Yeah.
01:27:17The barrel is buried deep in the mud.
01:27:20They'll have to pull very hard to get it out.
01:27:29It weighs over two tons, so it should go well.
01:27:32They're just discussing if the rope will take attention or not.
01:27:36Is it now a bad time to worry about that?
01:27:39That's what he's saying, it's no problem.
01:27:41Pull, pull, go on and pull. That's what he's saying.
01:27:44Okay.
01:27:45They're pulling.
01:27:52No sign of any movement yet.
01:27:57Can they tell how much force they're putting onto that winch?
01:28:00No, not exactly.
01:28:01Suddenly it will just pop free.
01:28:04Yeah, it will pop free.
01:28:05So it's hard to say exactly when it's going to happen.
01:28:11There's a slight movement in it, so...
01:28:15Okay, it's coming, it's coming.
01:28:16There it goes, it's coming, it's coming.
01:28:18There it goes, it's coming, it's coming.
01:28:22Okay, off it goes.
01:28:26Barrel on a bungee.
01:28:27Yep.
01:28:28And did you see the bottom of the barrel when it came out?
01:28:30Oh, yeah.
01:28:30The paint was still on it.
01:28:37Don't drop it.
01:28:42The underwater cameras on the ROV provide the first close look at the barrel in 60 years.
01:28:48It appears intact, but the smallest of holes is enough to contaminate any heavy water it may contain with lake
01:28:56water.
01:28:57Luckily, the process of electrolysis, which concentrated the heavy water, should have left traces, which will allow Dave to test
01:29:05for contamination.
01:29:08The barrels contain heavy water, we hope, but to make the heavy water, to separate it originally, they had to
01:29:14add something else to make the water conduct electricity.
01:29:17They added something called potash lye, which is actually potassium hydroxide, which will make the water very caustic.
01:29:24Now, we measure whether water is caustic or not on a scale called pH.
01:29:29Well, now we're going to want to know whether the pH in the barrel is different than the pH of
01:29:34the lake water, so I have to know what the pH of the lake water is.
01:29:37So, now I'm going to test it and find out.
01:29:41Okay, now you can see it's about...
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