Futility Closet - 181-Operation Gunnerside

Episode Date: December 11, 2017

  During World War II, the Allies feared that Germany was on the brink of creating an atomic bomb. To prevent this, they launched a dramatic midnight commando raid to destroy a key piece of equipment in the mountains of southern Norway. In this week's episode of the Futility Closet podcast we'll remember Operation Gunnerside, "one of the most daring and important undercover operations of World War II." We'll also learn what to say when you're invading Britain and puzzle over the life cycle of cicadas. Intro: Hundreds of students overlooked an error in a Brahms capriccio; a novice found it. Hesiod's Theogony gives a clue to the distance between earth and heaven. Sources for our feature on Operation Gunnerside: Ray Mears, The Real Heroes of Telemark, 2003. Knut Haukelid, Skis Against the Atom, 1954. John D. Drummond, But for These Men, 1962. Neal Bascomb, The Winter Fortress, 2016. Thomas B. Allen, "Saboteurs at Work," MHQ: The Quarterly Journal of Military History 26:2 (Winter 2014), 64-71. Ian Herrington, "The SIS and SOE in Norway 1940-1945: Conflict or Co-operation?" War in History 9:1 (January 2002), 82-110. Neal Bascomb, "Saboteurs on Skis," World War II 31:2 (July/August 2016), 58-67,6. Hans Børresen, "Flawed Nuclear Physics and Atomic Intelligence in the Campaign to Deny Norwegian Heavy Water to Germany, 1942-1944," Physics in Perspective 14:4 (December 2012), 471-497. "Operation Gunnerside," Atomic Heritage Foundation, July 28, 2017. Ray Mears, "Norwegian Resistance Coup," NOVA (accessed Nov. 19, 2017). Simon Worrall, "Inside the Daring Mission That Thwarted a Nazi Atomic Bomb," National Geographic, June 5, 2016. Andrew Han, "The Heavy Water War and the WWII Hero You Don't Know," Popular Mechanics, June 16, 2016. Gordon Corera, "Last Hero of Telemark: The Man Who Helped Stop Hitler's A-Bomb," BBC News, April 25, 2013. Tim Bross, "Sabotage Slowed Nazi's Pursuit of Atomic Power, Author Writes," St. Louis Post-Dispatch, May 1, 2016, D.7. Andrew Higgins, "WWII Hero Credits Luck and Chance in Foiling Hitler's Nuclear Ambitions," New York Times, Nov. 20, 2015. "Colonel Jens-Anton Poulsson," Times, Feb. 17, 2010, 65. Richard Bernstein, "Keeping the Atom Bomb From Hitler," New York Times, Feb. 12, 1997, 17. Howard Schneider, "Defusing the Nazi Bomb," Wall Street Journal, May 27, 2016. "Norwegian Resistance Hero Helped Halt Nazi Bomb Plans," Ottawa Citizen, Feb. 13, 2003, A6. E.W. Fowler, "Obituary: Heroic Saboteur Knut Anders Haukelid," Guardian, March 15, 1994. "War Hero Was Last Kon-Tiki Survivor," Edmonton Journal, Jan. 10, 2010, E.7. Listener mail: Modern mudlarkers, from listener Tom Mchugh: Wikipedia, "Petroleum Warfare Department" (accessed Dec. 9, 2017). Sir Donald Banks, Flame Over Britain: A Personal Narrative of Petroleum Warfare, 1946. Wikipedia, "KRACK" (accessed Dec. 9, 2017). James Sanders, "KRACK WPA2 Protocol Wi-Fi Attack: How It Works and Who's at Risk," TechRepublic, Oct. 16, 2017. Brad Chacos and Michael Simon, "KRACK Wi-Fi Attack Threatens All Networks: How to Stay Safe and What You Need to Know," PCWorld, Nov. 8, 2017. This week's lateral thinking puzzle was contributed by listener Sam Long. You can listen using the player above, download this episode directly, or subscribe on iTunes or Google Play Music or via the RSS feed at http://feedpress.me/futilitycloset. Please consider becoming a patron of Futility Closet -- on our Patreon page you can pledge any amount per episode, and we've set up some rewards to help thank you for your support. You can also make a one-time donation on the Support Us page of the Futility Closet website. Many thanks to Doug Ross for the music in this episode. If you have any questions or comments you can reach us at [e-mail]. Thanks for listening!

Welcome to the Futility Closet podcast, forgotten stories from the pages of history. Visit us online to sample more than 10,000 quirky curiosities from a musical misprint to the distance to heaven. This is episode 181. I'm Greg Ross. And I'm Sharon Ross. During World War II, the Allies feared that Germany was on the brink of creating an atomic This is episode 181. I'm Greg Ross. And I'm Sharon Ross. During World War II, the Allies feared that Germany was on the brink of creating an atomic bomb.

To prevent this, they launched a dramatic midnight commando raid to destroy a key piece of equipment in the mountains of southern Norway. In today's show, we'll remember Operation Gunnerside, one of the most daring and important undercover operations of the war. We'll also learn what to say when you're invading Britain and puzzle over the life cycle of cicadas. Heavy water, or deuterium oxide, is an unusual form of water. It's like H2O, but it has deuterium atoms in place of normal hydrogen atoms. of water. It's like H2O, but it has deuterium atoms in place of normal hydrogen atoms. In the 1930s, the world's only commercial producer of heavy water was the Vimork hydroelectric plant

in the southern mountains of Norway. That's an interesting plant. It's perched dramatically on a ledge or a shelf of rock over a gorge west of Oslo, and it's powered by snowmelt running down from the mountains. This plant had been designed in 1933 by Leif Tronstadt, who was a young Norwegian physicist who was interested in possible uses of heavy water. The Norwegians used it initially to make ammonia for nitrogen fertilizer, but Tronstadt thought it might be used for any number of other applications, including chemistry or biomedicine, or perhaps in studying atomic physics. He told his students technology first, then industry and applications. As he was considering these possibilities, two alarming things happened. In 1938, German scientists discovered nuclear fission, and in 1940,

Germany invaded Norway. Nuclear fission is alarming because it can be used to create an atomic bomb, and no one wanted to contemplate Nazi Germany getting its hands on one of those. And Germany invading Norway is alarming because it gave the Germans access to this heavy water at this plant. And heavy water is a key ingredient in making an atomic bomb. They needed to control the nuclear reactions that would produce plutonium. Tronstadt's fertilizer plant was the only large scale producer of heavy water in the world, and it was now under German control. So the Allies were very nervous about this. After they occupied Norway, the Nazis started to restrict the people's rights and starved and killed some of them.

So Trondstedt actually turned away from physics and started to spend more of his time on resistance activities. One of the things he did was set up a spy network to inform the British anonymously about what the Germans were doing. By September 1941, the Nazis had discovered that he was doing this and he had to flee to England. The British were happy to have him. He was valuable to know for any number of reasons. The scientists there wanted him for his knowledge of Norwegian industry, but he wanted to help his country, and instead he became chief of intelligence for the Norwegian government in exile, which had been set up in London. He got word from people back in Norway that the Germans had increased production of heavy water at this plant. By the end of 1941, they were putting out about four kilograms a day. That meant they were pursuing nuclear energy, possibly to build a reactor to make plutonium.

Churchill wanted to attack the plant to stop them from doing this. If the Germans got a bomb, London would likely be its first target. But it wasn't clear how you'd go about doing that. The Americans wanted to just bomb the plant, but Tronstad pointed out two problems with that. First of all, if they hit the ammonia storage tanks there, then the local civilian population could be hurt. And the second thing is, these heavy water facilities that they'd have to destroy were unfortunately all the way down in the basement

under layers of concrete and metal, so that even if you bond the plant directly, you might not manage to destroy them. Tronstadt recommended a small commando raid instead, and finally they agreed on that. Tronstadt was very valuable to the British, so they didn't want him himself to go and be one of these commandos, but he was very valuable in just training and informing them. He had informants back in the plan and elsewhere in

Norway who really helped to inform all the preparations for this stuff. And the commandos, the people they'd picked, went through grueling training in Scotland, climbing mountains, fording rivers, and camping outdoors for weeks. They'd need that because this Vamork plant is surrounded by a high mountain plateau. The plan started in October 1942 when an advance team of four Norwegian commandos landed by parachute on the plateau above the plant to gather intelligence and to make preparations. Their orders were to set up a system of radio beacons so that the next segment of the plan could go forward. The four men were dropped in the wrong place, and they went off course several times, so it took them longer than usual to get set up. By the time they reported

that they were ready, I just like this detail, the British had become suspicious and asked them, what did you see in the early morning? And the team replied, three pink elephants, which was the right response. This is just an odd question just to confirm that they were who they said they were, but I just like the idea of someone listening in on that and wondering what the heck was going on. Anyway, they got set up, and then a month later, in November 1942, two bombers set out from Scotland for Norway. Each of these bombers was towing a glider full of British soldiers who'd been trained in sabotage. The plan was that they would land near this plant and then demolish it with explosives.

But in the bad weather, everything began to go wrong. One bomber crashed into a mountain, and its glider managed to cast off before that happened, but then crashed itself nearby, killing three men. The other bomber was running out of fuel and had decided to abort the mission when its glider's tow cable snapped, probably due to the cold weather, and it too crash-landed on a mountain. The survivors of both of these crashes were captured and killed by the Germans, who tortured some of the men into revealing that their mission had been aimed at the Vomorgue plant. So this is almost the worst outcome you can imagine. They didn't accomplish anything, and they managed to put the Germans on their guard. They now realized that the Allies wanted to stop them from creating heavy water at this fertilizer plant. Gestapo units swept after

the original four-man team, which drove them back into the wilderness, but they didn't catch them. And now with the plan off track, those four men had no supplies and were forced to live off the land through the coldest winter in memory while the British worked on a new plan. They had to move around constantly to evade the Germans who were searching for them. The Germans realized they had a radio transmitter or were trying to communicate with their friends back in England. And so they got direction finding equipment and figured they could maybe triangulate and figure out where they were and nearly succeeded. Sometimes the Germans got so close that Knut Haukeli, who was their leader, could see them through his binoculars, but he still kept up his transmissions as often as three times a day

using fishing rods as antennas. They were really pretty desperate. And they were so hungry, they were reduced to eating moss and lichen until they finally managed to catch a reindeer just before Christmas. Anyway, while they were starving up in the wilderness, in Britain, the Allies were trying to decide what they ought to do, since this glider adventure had completely failed, pretty much. Since the gliders had crashed, they'd lost the element of surprise. The Germans knew they were after this plant, and now would be actively guarding it. To get past those defenses, the British decided to attack the plant using a small team of six Norwegian commandos who would use plastic explosives to blow up the heavy water containers

in the basement of the plant. They'd actually have to infiltrate it and get inside. This is all terribly dramatic. I should mention that this all turned into a Kirk Douglas movie, apparently, in 1965, which I haven't seen, which apparently is not a blazing paragon of historical accuracy. But just for the record, I think it's called the Heroes of Telemark. Anyway, Tronstadt trained these men as well, and apparently phenomenally well. Again, using inside information, he gave them photos, equipment diagrams, blueprints, intelligence reports, and even built a scale model of the facility so they knew exactly what they were going to have to do. He told them, for the sake of those who have gone before and fallen, I urge you to do your best.

Trust that your actions will live in history for a hundred years to come. On February 17th, 1943, this team flew to Norway and jumped from a bomber over the wilderness near the plant. Under their snowsuits, they wore British battle dress so that if they were captured, the Germans would blame the British for the sabotage and then not make reprisals against the local Norwegian resistance, which I think is smart. They landed in a snowstorm 19 miles from Haakali's group and loaded up two toboggans with supplies, weapons, and explosives and just searched around for a couple days on cross-country skis until they managed to meet up with the other team that was already there. Together, they planned to make their assault on the night of February 27th, 1943.

The commandos were led by a man named Joachim Ronneberg, who was only 23 years old. When they joined up with Haukeli's team, they numbered 10 men altogether. Haukeli, under this plan, would actually stay away from the action and away from the plant so that he'd be able to radio the success or failure of the adventure, whatever happened in the end. And the other nine men then approached the plant. They carried chloroform in their pockets to overwhelm any guards they found, and each had been given a cyanide capsule. They knew their chances were even at best. This is an incredibly risky and dangerous thing to do.

There were three ways to approach the plant, and all of them were terrible. You could come down from the mountains above through an area that was covered with minefields. That was one. The second way is basically to go in through the front door, which meant crossing a single-lane suspension bridge that was 75 meters long, 200 meters above a deep ravine, and heavily guarded. Or you could climb down to the bottom of the gorge, cross a half-frozen river, and then climb up a 500-foot cliff on the other side. Also, whichever of those choices you picked, the Germans had been alerted by the failed glider attack and had put mines, floodlights, and extra guards around the plant, so all of those were pretty dangerous. The group finally voted to try descending into the gorge, which is, I imagine, what I would have tried too. They clambered down into the ravine, crossed the river, which was thankfully low at that moment, and then climbed painfully up the farther side.

This took hours, and at the top they found a railway track, which they knew would lead them to the plant itself. Fortunately, they didn't meet any guards at the plant. The security in the plant itself had slackened somewhat for the winter months, although there was heavy guarding further out in the land around it. They reached the plant at 12.30 a.m., and Newt Haukeli used a pair of heavy-duty metal cutters to get through the fence. The fact that he had a pair of heavy-duty metal cutters to get through the fence. The fact that he had a pair of heavy-duty metal cutters was pure luck. He actually bought them in England in Cambridge after going to a movie on his day off.

He just happened to see them for sale somewhere and thought those might be useful when I go to Norway and just bought them. What the British military had given him to cut through the fence themselves was a handsaw, but he later told the New York Times that that would have taken too much time, made too much noise, and alerted the Nazi guards. So it's only luck that they're leaving to get into the building. After they got through the fence, the nine-man group divided into two smaller groups, a four-man explosive group and a five-man cover squad. British intelligence had a Norwegian informant in the plant, and he'd given them details, plans, and schedules. And following those, the explosives group had hoped to enter the plant through a side door. They found the door, but that turned out to be locked.

So Ronneborg and another man found an access tunnel instead. They crawled dozens of yards through a maze of pipes. This really sounds like a movie. And then dropped into the basement and made their way to the room that housed these heavy water cells that they wanted to destroy. There was a night shift worker there, but he was Norwegian and somewhat sympathetic, so they just told him they were British soldiers and that no harm would come to him if he cooperated. Ronenberg said later, getting inside, I was quite certain that the rest of the party would follow me, but only one chap came. The other ones hadn't found the entrance to the tunnel. Therefore, we decided we'd have to do it ourselves and started laying out the charges.

That meant arranging two strings of explosive charges around these heavy water electrolysis chambers. And they'd got most of the way there. Ronneberg was attaching explosives to the ninth cell when a window crashed in behind him. He turned around and raised his gun, but it was just the two missing members of the demolition team. They hadn't been able to find the door, so they just broke through the window. As they were making their final preparations, the Norwegian foreman showed up. So now they had two hostages, but he just put up his hands as well. So they just had two men to sort of watch over while I finished putting this together. The fuses on the explosives were designed to last two minutes, but after some thought,

Rønneberg shortened them to 30 seconds so his team would have time to escape, but they could still hear the explosion. He told the hostages that after he lit the fuses, they should run upstairs, lie down, and hold their mouths open so that their eardrums wouldn't be blown out. And then this kind of touchingly human moment just then, the guard said, please, I need my glasses. They're impossible to get in Norway these days. He left his glasses on the desk. And if he ran upstairs without bringing them, they'd be destroyed in the explosion.

And so he asked if they would get them, which they did. They sort of politely rummaged through his desk, found his glasses, and gave them to him, and he thanked them. It was kind of this polite little moment. Then Roneberg lit the fuses and everyone ran. The explosion actually wasn't as loud as the commandos had expected. One of them later said it sounded like two or three cars crashing in Piccadilly Circus, but Roneberg heard it and knew they'd succeeded. 500 kilograms of heavy water, everything that had been produced during the German occupation, went down the basement drains and equipment that was critical to the operation of the electrolysis chambers was destroyed. The commandos fled the plant and reconnected with the cover squad and the nine of them skied back to the mountain plateau where they

split up. Afterward, the explosives team skied more than 200 miles to Sweden and the cover group spread out through the plateau. The Germans, when they realized what had happened, sent 3,000 soldiers to chase them with aircraft searching overhead, but all of them got away. No one was killed or captured. Ronneberg called it the very best skiing weekend I ever had. Back in Britain, Tronstad received this confirmation. Operation carried out with 100% success.

High-concentration plant completely destroyed. Shots not exchanged since Germans did not realize anything. Germans do not appear to know whence the party came or whether they disappeared. One interesting, actually two interesting details here. To avoid reprisals against the local Norwegian resistance, the commandos had brought with them a Thompson submachine gun, a British machine gun, and left it there so that it would look as though this had been a British operation, which I think took a lot of forethought. And the second thing, which is hard to believe, is that Ronneberg didn't know what he had done. The British had only told him that there was a row of pipes at this Vamork plant that needed to be destroyed. He said they just said it was important and had to be blown up.

He knew that Britain had lost more than 35 men in the earlier attempt to sabotage the plant, the one with the gliders, but he didn't know why they'd chosen that goal. As far as he knew, it was just a remote mountain plant that made fertilizer. The British Special Operations Executive later declared this operation the most successful act of sabotage in all of World War II. Even the Germans were impressed with it. The head of German forces stationed in Norway, General Nikolaus von Falkenhorst, called it the best coup I have ever seen, and he was the victim of it. The raid had destroyed the heavy water production facilities, but not permanently. The plant was decommissioned for a few months, but by May 1943, it was operating again. And now the Germans obviously were on

their guard, so they'd improved their security. So the Britons thought that another commando raid might be extremely difficult. So in November 1943, the Americans just started bombing the plant quite heavily. 174 aircraft dropped 828,000-pound bombs. That destroyed a lot of the plant, but just as Trondstedt had predicted before, it left the heavy water canisters intact because they were all the way downstairs. And, as he'd also predicted, it killed 22 civilians, which infuriated the Norwegians, who weren't happy being occupied by Germany but didn't like to be killed, especially when there was nothing accomplished by it. Didn't want to be bombed by the Americans. Right. But it did accomplish this. The Germans were convinced by all this bombing that the Allies' attacks were just going to continue. So in early 1944, they decided to just abandon this plan and take the heavy water they had managed to make

and move that and some critical components back to the research centers in Germany. So here's—this gets more and more dramatic. The Allies realized this was going to happen. What they were going to do is take the heavy water on a ferry across Lake Tin, which is this deep mountain lake, to the railway on the other side to take it back to Germany. And as it turned out, there was only one trained Norwegian commando in the area, which turned out to be Knut Haukeli, who was the poor man who was starving and eating reindeer in the frozen wilderness just a year and a half before. So they told him, look, I'm sorry, you have to stop this somehow.

All by yourself. He managed to recruit two helpers, and they did, which again sounds just purely like something you see in a movie, they stole aboard the ferry that would be carrying the containers across Lake Tin. One of them engaged the guard in conversation while two others crept into the hold and set up some explosive charges against the wall of the hull of the ferry that would be triggered by an alarm clock. The ferry set off around midnight on February 20th, 1944, got halfway across the lake, and exploded and sank in more than a thousand feet of water. Fourteen Norwegians and four Germans died, but the Allies had finally fulfilled completely their mission. Now Germany could

not develop an atomic bomb. MRD Foote, the official historian of the British Special Operations Executive, described the raid on the Vmork plant as a coup that changed the course of the war and deserved the gratitude of humanity. Ronneberg, who led the raid, later said, there was no plan. We were just hoping for the best. He said, this operation wasn't Norwegian or British at all. It was an allied operation. In 2013, the BBC asked Ronneberg when he had finally realized the importance of what he'd done, and he said, that was in August 1945 when they dropped the bombs on Hiroshima and Nagasaki, and then we knew what we had done was of great importance. Not until then.

In hindsight, it's become clear that the Germans weren't as close to producing a bomb as the Allies had feared. They were never able to produce a successful chain reaction, partly because they were trying to use heavy water to control the reaction rather than graphite, but more broadly because their bomb program was just poorly coordinated and wasn't consistently supported by scientists, the government, and the military. At the time of the raid on the plant in February 1943, Germany had already slowed its research into atomic weapons, it turned out. In his memoirs, Albert Speer recalled that on the suggestion of the nuclear physicist, we scuttled the project to develop an atom bomb by the autumn of 1942.

But there seems to be some disagreement about that. Kurt Diebner, the director of Germany's nuclear energy product, wrote in his memoir that the obliteration of deuterium production in Norway was a major reason that Germany never developed a reactor. And in any case, we can't judge these things by hindsight. At the time, the Allies didn't know how far along the Germans were in their nuclear ambitions. They only knew that the Germans were very interested in heavy water, which could help them advance toward an atomic weapon. In fact, it was this very uncertainty that spurred the Americans to invest in the Manhattan Project and produce their

own nuclear weapon. Robert Furman, the chief of foreign intelligence for that project, said the Manhattan Project was built on fear, fear that the enemy had the bomb or would have it before we could develop it. Some historians have said that Germany would never have had a bomb before the Allies, even if they'd had a full supply of heavy water, but that's certainly a risk we couldn't take. Neil Bascom, who's written the fullest account of all this, writes, what if the Germans had fashioned a sustaining reactor with heavy water? What then? Joachim Moranenberg, the leader of the Vamork raid, is still alive and living in Norway. He's now his nation's most decorated living war hero. A statue of him was raised in Ullesen in 2014 to mark his 95th birthday. Inscribed on its base is the message, peace and freedom are not to be taken for granted.

If you're still searching for the perfect holiday gift, or maybe a fun little gift for yourself, check out the Futility Closet books. Both books have hundreds of short bites of mental candy, with a mix of quirky oddities and curiosities, offbeat inventions, odd words, and brain-teasing puzzles. Perfect for anyone who would like to learn more about a softball game played at the North Pole, or how the Greek king Periander concealed the location of his own grave. Look for the books on Amazon and see why other readers have called them awesome and addictive, and full of wonderful discoveries for the curious mind. Tom McHugh wrote about the mudlarking that I discussed in episode 174, the practice of searching the banks of the Thames at low tide for anything the river might have deposited. I'm a big fan of the podcast and had just finished listening to 174 last Sunday. Unfortunately, I had to go to work. My commute is over the Millennium Bridge that spans the Thames between St. Paul's Cathedral in North London and the South Bank, speaks for itself,

where you can find the Tate Modern Gallery and Shakespeare's Globe Theatre. Walking back from work, I saw dozens of tourists and locals mudlarking in the low tide. Not great quality images, but I was happy to see that the seemingly Dickensian pursuit of mudlarking still goes on in the city. Thanks for all your hard work on the podcast. It's a highlight of the week and not just of my commute. And Tom included two photos of people mudlarking, and that of course will have them in the show notes. I also have a follow-up from episode 174 on the book of German invasion plans that contained yet another language phrasebook of dubious benefit. Chris wrote, Hi, Greg, Sharon, and Sasha. The continued discussion about unhelpful foreign language phrasebooks reminded me of one from World War II. I had thought it was apocryphal,

but a couple of years ago I read a book that had a photograph of the document. Thanks for the always interesting podcast. And Chris sent scans of a leaflet and part of a 1946 book written by Sir Donald Banks, Flame Over Britain, A Personal Narrative of Petroleum Warfare. The Petroleum Warfare Department was established in 1940 as a consequence of Britain's fears of a German invasion during World War II, and it was charged with developing weapons based on petroleum. Sir Donald Banks was appointed the Director General, and it was charged with developing weapons based on petroleum. Sir Donald Banks was appointed the Director General, and Geoffrey Lloyd, the Secretary for Petroleum, told Banks that the goal of the department was, Flame all across Britain, ringing the coast, spurting from the hedges and rolling down the

hills. We will burn the invader back into the sea. With a small staff basically lacking in any useful technical knowledge, the department set to experimenting with various ways to use petroleum to try to defend Britain. Some of the trials involved, for example, blowing up a tanker carrying 50 metric tons of petroleum, or experimenting with setting the sea on fire by burning floating oil. These were not the kinds of tests that could be easily hidden from general view, as they produced pretty dramatic effects. And although many of the experiments didn't produce any practical results, it was soon realized that they could actually turn the experiments themselves to their advantage.

In his book, Banks wrote, perhaps the greatest contribution from all these variegated efforts was in building up the great propaganda story of the flame defense of Britain, which swept the continent of Europe in 1940. And this was a vigorous propaganda campaign to convince the Germans that Britain was quite capable of fiercely defending itself with fire should the Germans attempt to invade. As part of this fear-inspiring operation, in October 1940, the RAF dropped millions of leaflets written in the style of a tourist guide, purporting to be a list of useful phrases in German, French, and Dutch that would be needed

if you were to attempt to invade England. And thanks very much to my brother Bruce, who translated the French version for me. So here are some selections from Our Trip to England, a short conversation guide for the invasion. The sea is huge, cold, stormy. Will we ever get to England? Will we ever return from England? Why isn't the Fuhrer coming with us? Who has cut our phone lines again? Did you toss my comrade in the canal? Can you lend me a life vest or flotation ring? How much do swimming lessons cost? Is that a bomb, a torpedo, a grenade, a mine? Watch out, English attack boats.

Our ship is capsizing, sinking, burning, exploding. Our squadron, our company, our battalion, our regiment is sinking. The others, the whole division, the entire military is also. Where is our fleet, our air support? The sea reeks of oil here. Even the water burns here. See how well the captain burns. Carl, Willie, Fritz, Johan, Abraham is burnt to a crisp, has drowned, was torn apart by propeller blades. We've had enough. We are the only ones to get out alive. We want to go home. I sort of understand the idea of like sowing fear. I get that much of it. But I can't picture a German pausing to look up in a phrase book, the phrase, see how well the captain burned,

like the most arduous part of that whole experience would be looking it up in your book. I think the point was they were saying, these are the phrases you're going to need if you try coming to England. And then at the bottom of the leaflet, it said, a complimentary conversation guide in English will be provided to each invader when he arrives at the POW camp in Great Britain. Great Britain. But apparently this propaganda campaign was actually so successful that reports circulated through Europe that the Germans had attempted to invade England, but had been repulsed by the burning seas and had actually suffered heavy casualties. Banks said of the effects of the propaganda, it is difficult to assess the actual military results of all this, but that it had effect is without doubt. And he wrote that the Germans placed large orders for asbestos suits with a Paris manufacturer, and embassies in neutral European countries were reporting large-scale casualties of burned German troops. He said,

on the Loire and the coast, embarkation exercises were frequently carried out by the enemy, and it appeared that troop trials against burning oil resulted in more than one serious accident that filled the local hospitals. And he noted that the stories of the disaster by fire in the channel attained such strength and pervasiveness that it assisted in weakening the enemy's will to attack at this most crucial period. So that might make these leaflets one of the most effective of the odd phrasebooks that we've covered covered because apparently they really at least contributed to everybody believing that this really was going on. That whole story is just amazing to me that it happened at all. Yeah. Yeah. We didn't know a single word about this until Chris wrote in. So thank you very much for that email. Yeah. Very helpful. And lastly, we heard from Asher Dupre, aged 15, and Grizzly the Dog about the feature story in episode 174 about mathematician Arne Burling's success in breaking a very difficult German cipher in World War II. Greetings, closet dwellers! While listening to episode 174, Cracking the Nazi Code,

you mentioned that the likely way he cracked the cipher was due to a twice-sent message with slight differences. You might be interested to know that most Wi-Fi had recently been hacked in a similar way. A researcher recently figured out how to make a security key be sent twice, which allowed it to be cracked. It has since been fixed by most major manufacturers, Apple, Microsoft, but it is interesting to note the similarities. And that is an interesting similarity that Asher raises. Berling wouldn't say how he had cracked the cipher, but mathematicians thought that the most likely explanation was that he had relied on the Germans sometimes retransmitting parts of the messages using the same code. And Greg told us that doing that has

been called the cardinal sin of cryptography, but apparently modern day software developers had overlooked the possible dangers of this. And that has led to a potentially exploitable flaw in Wi-Fi protocols that could allow hackers access to a Wi-Fi network. A Belgian researcher recently discovered that the standard Wi-Fi protocol allows for an encryption key to be resent multiple times during the authentication process and that hackers could take advantage of this behavior to break the security encryption. I'm not aware that any attacks on Wi-Fi networks have actually been carried out using this crack or key reinstallation attack. It seems that at this point it's more a theoretical vulnerability. But that was a really good catch on Asher's part to see the parallels with Berling's story. It's interesting how the same principle applies in such completely different circumstances,

you know? It's sort of an abstract idea, but it applies just equally well in both cases. Right. So that was a good catch on Asher's part. Yeah. Asher also wrote, I love listening to Futility Closet and am especially impressed by your speed in solving lateral thinking puzzles. At school last year, it took us about 30 minutes per puzzle and we were doing it as a class.

And there I have to say that we do cheat a little bit as we're careful to try to choose puzzles that can be solved in just a few minutes, given the time constraints of the show. And we also give hints to help keep the puzzles moving along, which maybe Asher's teacher didn't. Some puzzles have complicated or very difficult to guess stories that would make them a lot of fun to do as a class or in situations where you have a lot of time. But unfortunately, that kind of puzzle doesn't work out very well for our podcast. So we just have to be careful

about which ones we try to use. Or we just try hard ones and fail and then just don't put those on the show. And then they don't, that's right. There's a lot of that. They don't end up on the show. So thanks so much to everyone who writes into us and to Sasha, whose contribution

to this section this week was to walk on the keyboard as I was researching and writing up my notes. She added an almost full line of Q's ending with an S and a Z. And I ignorantly didn't know how to pronounce that. So I had to discard what I'm sure was her very valuable input. But if you have anything you'd like to send in to us that's a little more readable than that, please send it to podcast at futilitycloset.com.

And thanks again to those who, like Asher, provide pronunciation tips for their names. It's my turn to try to solve a lateral thinking puzzle. Greg is going to give me an odd-sounding situation, and I have to try to figure out what is going on, asking only yes or no questions. This is from listener Sam Long, who is a biology teacher. Uh-oh. Is that relevant? Yes. He says, The cicada is an insect known to spend its youth living underground,

then emerging briefly for a few weeks to mate and die while its offspring burrow underground and repeat the cycle. A certain brood of cicada undergoes this life cycle with a period of exactly 17 years between generations emerging from the ground. Why did the cicada evolve to have a life cycle of exactly 17 years? Ah. Ha. Um, that is a good question, because I knew about the 17 years, but I never stopped to think why.

Okay, does this have to do with the life cycle of something else that, like, eats cicadas? Yes. Oh, it does! I was trying to of something else that like eats cicadas? Yes. Oh, it does. I was trying to think what else would evolution, you know? So do I have to figure out what, okay, what eats cicadas and has a different life cycle? 17 years is such a weird. Yeah, specific. Yeah.

What eats cicadas? Is it something reptilian? You don't have to know. Oh, oh, oh. You know it's a predator. You don't have to know what it is. It's a predator. Is it something reptilian?

You don't have to know. You know it's a predator. You don't have to know what it is. It's a predator. And it must have some kind of cycle that is very, very different than 17 years, right? I mean, like something that eats cicadas only in part of its life cycle? Or I'm trying to figure out how this all works. I get that it's a predator. There's a cicada predator.

And it only eats cicadas or it would only eat cicadas or multiple predators even possibly or multiple predators and they all eat cicadas and they all eat cicadas

but somehow by the cicadas only coming out every 17 years oh is it that the lifespan of the predator is shorter than 17 years

so they wouldn't learn to eat cicadas you're very much on the right track but it comes down to specifically the number 17. Specifically the number 17. It's a prime number. It's predators that don't like prime numbers.

You're on the right track. Keep going with that. Is it got to do that it's an odd number? No, specifically that it's prime. Specifically that it's prime. Oh, because if it wasn't prime like it would sync up eventually with the lifespan of these other predators they'd be more likely to get eaten sam writes the cicada evolved the 17-year life cycle in order to avoid emerging from the ground during upticks in

populations of its predators suppose the cicada has a predator whose mating cycle results in peak predator populations occurring two years apart since 17 is not divisible by two, the cicada's next emergence from the ground would not coincide with the time of peak predator population, and that generation of cicadas would have a higher chance of survival and reproduction. Similarly, the cicada would be able to avoid other predators with mating cycles of three, four, and five years, etc., because 17 is a prime number.

This evolutionary pressure led to the 17-year cicada alongside a separate lineage of 13-year cicadas. Wow, the importance of prime numbers for biology. Thank you, Sam. Thank you. And if anybody else has a puzzle they'd like to send in for us to try, you can send it to us at podcast at futilitycloset.com. Futility Closet is a full-time commitment for us. If you would like to help support the celebration of the quirky and the curious that is Futility Closet, you can find a donate button in the support us section of the website at futilitycloset.com

or you can check out our Patreon campaign at patreon.com slash futilitycloset. We can also always use help spreading the word about the show, so please tell your friends and family about us or leave us a rating and review at Apple Podcasts or your favorite podcast platform. If you want to check out the website at futilitycloset.com, you'll find over 10,000 concise curiosities, the Futility Closet store, more information about the books, and the show notes for the podcast, with the photos and references for the topics we've covered. If you have any questions or comments for us, you can email us at podcast at futilitycloset.com. Our music was written and performed by the awe-inspiring Doug Ross. Thanks for listening, and we'll talk to you next week.