How WWII Became a Global War - Pearl Harbor, U-Boats, and the Fall of Empires

[00:00:11]October 1940.

[00:00:13]In a tight presidential election, Franklin D. Roosevelt is running for an unprecedented third term.

[00:00:21]As war rages across Europe, he sends a message to the American public. I have said this before, but I shall say it again and again.

[00:00:34]Your boys are not going to be sent into any foreign war.

[00:00:42]The American public are almost universally opposed to the idea of going into war. So if Roosevelt gets branded as a wararmonger, he's going to lose that election. Even after the fall of France in 1940, over 85% of Americans oppose sending US troops into an overseas [music] conflict.

[00:01:03]Less than 16% of the American public support even sending aid to the belleaguered allies in Europe.

[00:01:12]He could see the signs and he knew the United States would eventually have to enter this war on some level, but he has a voting base that he has to answer to.

[00:01:23]FDR wins the election, but he cannot keep his promise.

[00:01:28]>> By the end of Roosevelt's time in office, nearly 15 million Americans will have fought in this world war.

[00:01:52]Summer 1940.

[00:01:54]Even as President Roosevelt promises to keep America out of the war, on the other side of the Atlantic, a belleaguered Winston Churchill is looking for a fight. Britain is in pretty dire straits. The Battle of Britain is being waged overhead. The British Expeditionary Force has been thrown out of Europe. So what is needed is some kind of arena, some kind of theater of war where Britain can fight and where Britain can succeed.

[00:02:23]Churchill finds it in the Mediterranean.

[00:02:26]>> The Mediterranean theater wasn't just important as a means of allowing the British to fight. It was actually strategically very, very important.

[00:02:35]>> We actually got our oil from the Persian Gulf and that had to come through the Sueis Canal right through the Mediterranean. If Britain was to be thrown out of Egypt, it would lose that access to its oil.

[00:02:49]>> The Middle East can provide Britain with over 126 million barrels of oil a year.

[00:02:56]It's a vital resource transported from the Persian Gulf through the Suez Canal.

[00:03:04]In June 1940, Italian dictator Bonito Mussolini, who already controls neighboring Libya, decides to take Egypt and its precious waterway.

[00:03:16]>> Mussolini had real delusions of grandeur, a sense of his own importance.

[00:03:21]>> He sees Adolf Hitler in Germany grabbing for territory to create a new German Empire. And what Mussolini wants to create is a new Roman Empire in the Mediterranean basin. The plan basically was to seize control of the entire North African coast [music] to take it away from Britain.

[00:03:41]>> It's the fight that Churchill is looking for, but the numbers weigh heavily against him.

[00:03:49]250,000 [music] Italian troops land in Libya and march on Egypt against a mere 36,000 Brits.

[00:03:59]On paper, it looks like it's going to be an easy campaign, >> but the battle wasn't carried out on paper. A sudden attack by the British forced the Italians back.

[00:04:12]By February 1941, the British have advanced 500 m, captured 130,000 Italians, 380 tanks, and 1,290 artillery guns.

[00:04:27]Britain loses less than 2,000 killed and wounded.

[00:04:33]A furious Hitler diverts to the desert two divisions earmarked for the invasion of Russia.

[00:04:40]Named the Africa Corps, the new force is commanded by General Irvin RML.

[00:04:46]>> RML's leadership was what turned the Africa Corps into one of the most iconic units of the entire war. Because British tanks outnumber Germany's by more than 3 to one, RML is advised not to attack.

[00:05:01]>> But Raml simply ignored what he was told. He saw his opportunity and he launched a sudden attack.

[00:05:12]It might seem suicidal, but RML has an ace up his sleeve.

[00:05:19]The 88 mm flack cannon designed as an anti-aircraft gun. RML knows that it's also an effective tank killer.

[00:05:29]>> Just like he did in France, RML drew out the British forces into an area, ambush them then with the 88 mm guns.

[00:05:42]>> It took the British completely by surprise. What the British had just done to the Italians, Raml did to the British.

[00:05:50]>> By April 1941, Churchill's initial desert victory is in tatters.

[00:05:58]Romel has the British under siege at Tbrook and they have more to worry about than just North Africa because Mussolini has taken the fight to the Mediterranean.

[00:06:11]After a botched invasion of Egypt, the Italians preside over a botched invasion of Greece.

[00:06:17]>> In response, Churchill diverts 62,000 troops from the desert to defend Greece.

[00:06:24]>> Churchill sees this as a great opportunity to score yet another quick victory over the Italians. But the problem is is that Hitler then looks at what happens and decides he has to clear up the mess just as he did in North Africa. What does that mean? The British are now fighting a far more capable German force.

[00:06:44]>> In less than 3 weeks, Hitler's panzas overrun both Greece and Yugoslavia, forcing the British to evacuate 43,000 troops to the island of Cree.

[00:06:58]Hitler responds by launching an airborne invasion of Cree with up to 30,000 paratroopers backed by 480 bombers.

[00:07:07]British forces are effectively trapped.

[00:07:09]Winston Churchill orders General Waverl to stay there and fight to the last man.

[00:07:14]Waveville realizes that it's not a good idea and defies the order and evacuates 16,500 men.

[00:07:22]>> Waveville is dismissed for disobedience, but his decision saves British lives.

[00:07:28]>> 16,500 men live to fight another day. If that had been Hitler, those 16,500 men would have been needlessly squandered.

[00:07:38]These events profoundly affect the war, even outside the Mediterranean because the time it takes Hitler to chase the British out of Cree, has a domino effect on Germany's invasion of Russia. By delaying Operation Barbar Roa, even by one month, that pushes the Germans one month closer to the onset of Russian winter, and Russian winter will grind them to a halt. The situation in the Mediterranean is absolutely crucial for the outcome of the war.

[00:08:08]>> The British troops evacuated from Cree are sent back into the desert against RML.

[00:08:14]But the conflict will soon find itself mired in the vast expanses of the desert itself.

[00:08:22]First the British had the upper hand, then the Germans took the upper hand, then the British took it back. And the reason for that was because of supply lines.

[00:08:33]>> Germany's supply line starts in Tripoli, Britain's in Alexandria.

[00:08:39]A distance of almost 1,200 miles of desert that makes sustained advance by either side too difficult to refuel and rearm. The result is inevitable deadlock.

[00:08:53]There was no obvious end to this. What was actually going to change, make a sudden difference and end this conflict?

[00:09:02]>> The surprising answer will take place on a tiny island on the other side of the world.

[00:09:13]June 1941, over 4 million soldiers are locked in a devastating campaign across a 2,000m long front.

[00:09:23]In what is already one of the bloodiest conflicts in human history, the invading army grinds forward into a seemingly endless country, China.

[00:09:37]The campaign in China is a major all-out continental conflict for the Japanese that is costly.

[00:09:46]>> Japan has already lost over 1.8 million soldiers and committed more than 70% of its economy to war.

[00:09:55]>> The Japanese had got themselves into a situation where they felt that expanding the war was the only way that they could bring about a conclusion.

[00:10:04]A Japanese occupation of key airfields in Indochina greatly worries the American president.

[00:10:12]>> Roosevelt is in a really tricky position. He really wants to stop this Japanese expansion throughout Asia, but he can't do anything about it militarily. So what does he do? He's got to use America's economic muscle.

[00:10:25]Roosevelt takes the decisive move of freezing Japanese assets in the United States, which freezes millions and millions of yen. That then turns into this outright all-encompassing oil embargo. Japan imports 90% of its oil from the US. And for the Japanese, that feels like castration. To further demonstrate America's resolve, US aid to China is doubled.

[00:10:53]The powerful Pacific Fleet sails out of California to Pearl Harbor in Hawaii.

[00:11:00]35 B7 bombers are based in the Philippines within striking range of Japan. Roosevelt's hoping that if he flexes his military muscle, then Japan will back down.

[00:11:13]>> But he's reckoned without Japan's [music] desperate need for oil.

[00:11:18]>> The Japanese were backed into a corner and they basically had two options.

[00:11:22]Option A was that they could discontinue the war in China, which was certainly the American objective, or option B was that they could double down and expand war in Asia. And the Japanese chose option B.

[00:11:37]The Japanese army is under the control of General Hideki Tojo, aka the Razer.

[00:11:45]In October 1941, Tojo becomes prime minister and draws up plans to create a new Japanese southern resources area.

[00:11:56]>> The Japanese military began to think, well, where can we get additional resources? And the obvious place is Southeast Asia. Resources from British Malay, from Burma, from Dutchies, Indas and so on.

[00:12:07]>> It's a plan to take over all of Southeast Asia. Its code name is Operation Zed.

[00:12:16]Operation Zed allows 50 days for the conquest of the Philippines, 100 days for Malaya, and 150 days for the Dutch East Indies before pushing on into Burma and even India.

[00:12:32]Tojo's plan amounts to conquering roughly a sixth of the world's surface in just 6 months.

[00:12:40]Doing so will make armed confrontation with the industrial might of America unavoidable.

[00:12:47]At first glance, this seems insane. This is crazy. Japan has got to land a knockout blow in the very first round if she wants any chance of succeeding.

[00:13:02]The USA is the largest economy in the world, producing more steel, aluminium, and oil than every other major state combined.

[00:13:12]It produces goods worth over a trillion dollars a year.

[00:13:18]Japan's economy produces only 196 billion, more than five [music] times less than the USA.

[00:13:27]But these numbers count for nothing to Tojo because Japan has one thing the Americans can never match.

[00:13:35]Warrior spirit.

[00:13:40]If you join the Japanese army at that point, the training was very focused inspired by the tradition of what was known as bushido, the way of the warrior. There was [music] a strong psychological element that enabled the Japanese to feel that there was something superior and resilient about the Japanese military training.

[00:14:05]By contrast, they think that the Americans are kind of soft and a bit liy livered, just a nation fit for making movies and motorcars with no stomach for war. Many of the Japanese leaders thought that if they could hit the Americans hard enough, they would make terms immediately. They certainly didn't think of them as real warriors, people whom uh could resist Japanese soldiers for 5 minutes.

[00:14:31]>> Tojo has also run the numbers and he believes the Americans aren't ready to fight. You might expect that the world's most powerful economy is going to have a military to match it. But in 1941, the American economy is not geared for war.

[00:14:45]It's geared for commerce.

[00:14:48]In 1941, American military spending accounts for just 2% of its national output. Compared to Japan's 70%.

[00:14:58]>> The United States actually had a relatively small army. It was the 18th largest army in the world. The United States of America was unprepared for war. But the United States had an excellent navy.

[00:15:12]The United States in the inner war period had developed naval aviation to a level that it was among the leaders of the world.

[00:15:20]All of America's strength lies in its navy.

[00:15:24]In almost every class of ship, its power in the Pacific is almost equal to Japan's.

[00:15:31]But without its warships, America cannot hope to repel a Japanese onslaught.

[00:15:37]>> The Japanese thought that once you neutralize the American Pacific fleet, they would be reasonably secure.

[00:15:42]Americans would huff and puff and so would not actually engage in in serious war.

[00:15:48]>> Tojo needs to take out the US Navy and his intelligence network provides him with the opportunity.

[00:15:56]He finds out this vital piece of intelligence that the entire US Pacific fleet is going to be at Pearl Harbor in Hawaii.

[00:16:06]Too tempting a target to pass up.

[00:16:11]Located 2,500 m west of Los Angeles on the Hawaiian island of Aahu, the port of Pearl Harbor is the largest American base in the Pacific. And on paper, it's formidable.

[00:16:25]of Aahu by 1941 had been turned into the Death Star. Aahu had coast artillery positions and batteries. Effectively, all approaches were extremely well covered.

[00:16:37]>> They appear strong. In fact, the island's defenses are limited.

[00:16:42]>> What Aahu was well prepared for was a direct amphibious assault that was supported by battleships. What Aahu was less prepared for was this new thing called the air raid.

[00:17:01]On the 7th of December 1941, the first wave of the most powerful naval air force ever assembled flies low towards Hawaii.

[00:17:12]A grand armada of 49 bombers, 40 torpedo bombers, 51 dive bombers, and 43 fighters is heading for Pearl Harbor.

[00:17:24]These are very, very experienced air crew. They've been fighting in China for 4 years. Each man has on average 800 hours of combat experience.

[00:17:36]As 183 planes close in, 130 ships of the US Pacific Fleet sit at anchor in the bay and nearly 400 aircraft are parked on the ground. The position is impossibly vulnerable. Only a quarter of the machine guns guarding the harbor are actually manned and the anti-aircraft guns don't even have any ammunition. And worse still, it's the weekend, so most of the high command are taking some time off and leaving just some junior cadets in charge. It's hopeless.

[00:18:11]>> Before a single bomb has been dropped, commander of the Japanese airfleet Mitsuo Fushida gives the victory signal.

[00:18:19]Torah, tora, tora.

[00:18:23]>> The fighters and the dive bombers now peel off and they attack the air bases.

[00:18:33]The Japanese are carrying out a well-coordinated attack against every installation on the island.

[00:18:41]The Japanese torpedo bombers along with five mini submarines then go for the battleships.

[00:18:51]The Arizona takes a direct hit and that goes down with its crew of 1,500 men.

[00:18:57]Within minutes, Arizona's exploded.

[00:18:59]Oklahoma is capsizing. Utah is capsizing.

[00:19:06]At 9:00 a.m., a second wave of 167 aircraft hits the base to finish off the fleet.

[00:19:15]They leave behind a landscape of destruction.

[00:19:20]>> The Japanese destroy 188 aircraft, damage and sink 21 warships.

[00:19:27]and they kill just under 2500 Americans, both military personnel and civilians.

[00:19:34]>> But something is missing from the kill list. Admiral Yamamoto has been told that all US aircraft carriers are absent.

[00:19:44]Actually, all the aircraft carriers have been sent to Midway where they're acting as a kind of forward defense shield. But Yamamoto suspects they're being held back as a trap.

[00:19:54]It's enough to persuade him not to risk a third attack wave aimed at Pearl Harbor's undamaged refueling stations.

[00:20:03]>> The third wave could have knocked out Pearl Harbor completely, but Yamamoto simply can't afford to take that risk.

[00:20:11]At that point, the fleet had turned and was sailing away.

[00:20:18]The day after Pearl Harbor, President Roosevelt makes a speech to the US Congress calling for a declaration of war.

[00:20:27]>> December 7th, 1941, a date which will live in infamy.

[00:20:36]The United States of America was suddenly and deliberately attacked by naval and air forces of the Empire of Japan.

[00:20:50]But Japanese high command has utterly misjudged the American response to their [music] attack.

[00:20:57]The Japanese attack on Pearl Harbor was extremely effective at off the American people. It inspired a hatred of Japan, a rage and anger which unified the country as nothing else could have done. They completely misread that move. In Congress, the motion to declare war passes almost unanimously.

[00:21:18]Pearl Harbor has united America against the Axis powers, and the whole world is now officially at war.

[00:21:34]Even as the first bombs drop on Pearl Harbor, Japanese forces are already on route to their Southeast Asian resource zone.

[00:21:47]Their biggest target is British Malaya and its capital, Singapore.

[00:21:52]It's been said that if India was the jewel and the crown of the British Empire, then Malaya was the industrial diamond.

[00:22:02]In today's prices, Malaya is worth over 10 billion pounds a year, and 23% of its trade also passes through Malayan ports.

[00:22:14]Administering and profiting from this industry are 31,000 Europeans living a life of imperial luxury among 5 million Malaise and Chinese.

[00:22:27]Life in the colonies has not really changed since the 19th century. You've got this endless round of garden parties, cricket matches, social events.

[00:22:37]Physical separation between the white and Asian populations is enforced in workplaces, restaurants, and neighborhoods.

[00:22:50]The Japanese site European imperialism in Asia as a key driver of their expansion into the so-called southern resource zone.

[00:22:59]The Japanese used a very strong argument that it was they who were actually liberating other parts of Asia through the imposition of their own empire from the control of the British and the French. Now, in fact, this was a deeply deceptive idea. Japanese Empire was often just as brutal or even more so.

[00:23:24]When the Japanese invade Malaya, its defenders are undere equipped and undermanned.

[00:23:32]There are only 10 British battalions stationed in the province, accompanied by 145 aging Buffalo fighter and blenim bomber aircraft.

[00:23:45]These are not very good planes. They're slow. They're not very maneuverable. And the Japanese Zero can absolutely outfight them.

[00:23:56]On day one, nearly 100 British planes are shot down, leaving just 50 against nearly 600 Japanese.

[00:24:10]But Britain still has its most powerful weapon in hand.

[00:24:15]Months before the invasion, Winston Churchill sends to the Philippines an elite Royal Navy fleet known as Force Zed.

[00:24:24]Led by the HMS Prince of Wales, Britain's most sophisticated modern battleship, and the HMS Repulse, its most decorated cruiser.

[00:24:35]Within a day, they're suddenly attacked by this Japanese air force, and the British fleet has got no air cover at all.

[00:24:46]Both flagships are sent to the bottom of the ocean, taking with them the invincibility of the Royal Navy.

[00:24:56]These sinkings produce a shock wave that resounds around the world because these ships have been brought down quickly with small, lightly armed aircraft.

[00:25:09]>> Having sunk the Royal Navy, Japan sends in 60,000 ground troops. The ferocity and guile of the Japanese invasion takes the British by surprise. Japan's plans depend upon the kind of blitz creek tactics the Germans used against the French and the low countries uh back in 1940.

[00:25:28]But actually malair is a very different type of terrain than Europe. It's crisscrossed by lots of rivers. It's jungle. And so motorized transport doesn't really work as effectively in those sort of conditions. So, Japan comes up with this ingenious solution.

[00:25:45]It's called the bicycle.

[00:25:49]This is a 1930s bicycle, not a million miles away from the bicycle used by the Japanese army in the invasion of Malaya in 1941.

[00:25:59]Every Japanese division had 6,000 of these things. The Japanese soldier could carry himself, his equipment, and his ammunition. But more importantly, you can go through the jungle with it. You can go virtually anywhere. Even if the tire shredded completely, you could run on the rims. And there are stories about British units panicking, hearing these metal rims clattering down roads and assuming that they were tanks. But the key feature of the bicycle is it doesn't require fuel. The Advance can go ahead in almost any conditions without the need for any motor transport.

[00:26:41][music] The British chose to defend the roads and to position their troops around the roads and the Japanese with large forces of bicycles which they exploited brilliantly. Simply whenever they met the the British, they went round them.

[00:26:58]To reach Singapore, Japan's bicycle army advances on average 12 m a day for 55 days. 660 mi, 95 fighting engagements, and 250 bridge repairs later, they reach their target.

[00:27:18]The British simply don't expect any attack to come from the north. Why?

[00:27:22]Because it's jungle.

[00:27:28]But out of the jungle spring 30,000 Japanese.

[00:27:33]>> The 70,000 defenders are completely unprepared for the Japanese attack.

[00:27:38]>> The numbers favor British colonial forces by more than 2 to one, but many lack the will to fight.

[00:27:46]After years of social exclusion, many of the colonial native troops are absolutely unwilling to die with their British masters. Why would they want to?

[00:27:55]In fact, some even actually welcome the Japanese troops.

[00:28:00]>> On the 15th of February in 1942, Singapore surrenders.

[00:28:07]>> The British suffered in in Malaya not just a defeat but a humiliation because these despised orientals who were supposed to be near savages. Yes. In the minds of many British people, they wiped the floor with British and Australian troops. The Germans had estimated that it would take 16 divisions and that it would take months to reduce Singapore and produce its surrender. And the Japanese did it in a couple of weeks with two divisions.

[00:28:38]A bell rings out across Singapore signaling the surrender. And there's this classroom of school children. They ask their teacher, "What's that bell for?" And he replies, "The end of the British Empire.

[00:28:57]in the Philippines and determined to avoid such humiliation are the Americans.

[00:29:04]>> The Philippines are America's largest foothold in the Pacific and as a result, Japan desperately needs to conquer them.

[00:29:12]The Philippines are commanded by US General Douglas MacArthur.

[00:29:17]Within 10 hours of the Japanese strike on Pearl Harbor, he finds himself facing a devastating attack.

[00:29:25]>> The Japanese attack initially comes in the form of air raids followed by Japanese amphibious landings on the island of Luzon.

[00:29:37]and General Douglas MacArthur, commanding American and also Philippine forces, makes a tactical decision that the way he will fight will be to back down this peninsula that's on the western side of Manila Bay that's called Batan.

[00:29:54]Besieged by almost 200,000 Japanese troops, MacArthur is outnumbered 4 to one and he has 25,000 [music] civilians under his protection.

[00:30:08]Pummeled by relentless Japanese bombardment and racked with rampant malaria, MacArthur's force resists until February. But the situation is hopeless.

[00:30:20]MacArthur realizes that he simply can't hold out any longer. So, he's ordered to abandon the Philippines and he gets on board a torpedo boat and he turns and waves the people he's leaving behind.

[00:30:31]And he says, "I shall return." He was ordered to leave the Philippine Islands so that we would not have to face something as the British faced at Singapore where you see this well-known general come out and surrender to the Japanese.

[00:30:46]>> The 11,500 [music] American and 64,000 Filipino soldiers left behind are rounded up.

[00:30:55]>> Forces that surrender on the Batan Peninsula then have to be [music] moved to a prisoner of war holding area at a place called Camp O'Donnell 68 miles.

[00:31:03]and they are forced to cover that distance on foot.

[00:31:08]>> So many prisoners die on the infamous 68 mile walk to Camp O'Donnell that it becomes known as the Batan Death March.

[00:31:18]The Japanese force thousands to march through these absolutely appalling conditions and along the way uh they chop off the heads of American officers with samurai swords. Uh they just sort of run bayonets through Filipinos. It's basically murder and about,00 Americans are killed along the way along with 5,000 Filipinos. It's utterly horrific.

[00:31:45]>> The way is now clear for the Japanese to assault their key targets.

[00:31:51]Once they control Malair in the Philippines, the Japanese are now ready to take the Dutch East Indies and Burma.

[00:32:00]Now, these are vital for the Japanese cuz they're going to get 70% of the world's tin, almost all the world's rubber, and massive oil reserves.

[00:32:12]>> It also opens the way towards Australia with unexpected results that forces Australia to then recall troops that were committed in the North African desert. And so the Australians who are opposing Italians are pulled back toward Australia, leaving a vacuum there that emboldens Axis forces in North Africa. It's a completely unforeseen consequence of something that's become a truly global war.

[00:32:46]And this is a global war in more ways than one.

[00:32:51]As the Americans retreat to lick their wounds, they have more than just Japan to worry about.

[00:32:58]>> You've got Hitler knocking on the gates of Stalingrad, and then you've got the British massively on the back foot in North Africa. And what's worse still for the Allies is that Hitler's yubot are wreaking havoc in the North Atlantic.

[00:33:16]Unable to conquer [music] Britain, Hitler decides to starve her into submission instead. As an island nation, Britain is 50 million mouths to feed and 2/3 of the food that it uses to feed those mouths comes from abroad.

[00:33:30]>> Britain required at least 23 million tons of supplies a year just to keep alive.

[00:33:38]And to continue fighting, Britain also relies on imported raw materials.

[00:33:45]90% of its copper, 90% of our weapons grade barkite, and 95% of its vital oil and rubber come mostly from the United States.

[00:33:58]But Britain is on the verge of financial collapse. So in March 1941, President Roosevelt forces through the Lend Lease Act. inreasing numbers.

[00:34:10]>> A credit lifeline that allows Britain to buy whatever it needs from the US >> and pay for it later.

[00:34:18]>> America didn't want Britain to fall to the Nazis because we were the last bastions of the free world in Europe.

[00:34:26]>> Without American support, then Britain wouldn't really be able to stay going.

[00:34:31]To survive, convoys of Britain's 3,000 strong merchant fleet constantly traverse the Atlantic.

[00:34:40]Protecting them is the British Royal Navy.

[00:34:45]But lurking beneath the surface is a fleet of deadeyed hunters on a mission to destroy them all.

[00:34:55]Their submarines, Germany's yubot.

[00:35:02]The Yubot itself is capable of intercepting the aid that's being shipped across the Atlantic and potentially even stopping the flow of goods reaching Britain. If not stopping it entirely, at least slowing it to a trickle to the point that Britain can be brought to its knees.

[00:35:24]Submarine fleet Admiral Carl Donitz calculates that goal requires 600,000 tons of Allied shipping to be sunk every month.

[00:35:36]He asks Hitler for a fleet of 300 yubot but gets just 43. Adolf Hitler underestimates what the Yubot's capable of. It's his one and only true strategic weapon during the Second World War and he undercuts it. He doesn't think that [music] they're capable of delivering warwinning results which they easily could have produced.

[00:35:57]>> But even in small numbers, yubot are devastating, accounting for 70% of ships sunk by the German Navy. There is a sense I think in which the Ubot arm which is very small in 1940 sometimes only a dozen boats at sea outperforms its limitations and extracts a huge toll from British and later on American and Canadian shipping prowl the 600m wide mid-Atlantic gap known to sailors as the black pit because it is out of range of Allied air cover.

[00:36:40]Donuts maximizes his small fleet kills by sending them to hunt in wolf packs.

[00:36:46]>> A wolf pack would operate in coordination with one another. A group of, say, five Ubot drove a wedge into a convoy.

[00:36:56]They separated the faster ships from the slower ships. And if they could separate the convoy, it was easy hunting.

[00:37:03]>> Wolf packs are devastating.

[00:37:06]sinking a full quarter of British shipping in the first year of the war.

[00:37:12]Then in early 1941, they reach Admiral Donit's target of 600,000 tons a month and push Britain to breaking point.

[00:37:22]>> They were in a target-rich environment.

[00:37:25]And they were they were the hunters.

[00:37:31]When up to 57 men live for 6 months in a cramped metal tube in which they're liable to drown or be blown to smitherines, unshakable commitment to their cause is vital.

[00:37:46]The average age of the Yubot crewman was 21 years old.

[00:37:51]These are young people who had grown up uh under Nazi indoctrination. And so they were raised to do exactly what they were told. and they were raised to put up with quite horrifying conditions.

[00:38:03]>> It was really a floating metal coffin.

[00:38:07]>> 75% of Ubot men perish, among the highest mortality rate of any of the war's armed services.

[00:38:18]It's a terrible sacrifice, but for German high command, it's worth it because the Wolfpacks are delivering.

[00:38:26]For the German submariners, this period was known as the happy time. It wasn't the happy time for Churchill. He later wrote about it being the only time in the war where he was genuinely scared.

[00:38:40]>> April 1941, in the Atlantic Ocean, the British Navy hunts for German yubot, but they cannot find them because they don't know where they are.

[00:38:51]The German hubot are guided by messages which are encrypted in undecipherable codes.

[00:38:58]>> The encrypted codes are produced by Enigma, a machine that can produce a mind-boggling 1,253 trillion code combinations.

[00:39:10]Until Enigma is deciphered, Britain risks defeat and even starvation.

[00:39:17]To crack the Enigma machine, all the greatest minds are assembled [music] at Bletchley Park in Buckinghamshire, including the famous mathematician Alan Turing.

[00:39:31]Based in Hut 8 at Bletchley's government code and cipher school, 29-year-old Turing has his work cut out because the Germans reset Enigma daily.

[00:39:43]that these encrypted messages were believed by the German regime to be unbreakable.

[00:39:49]>> The human mind is not capable of running through the potential settings quickly enough because there are only 24 hours in a day and the codes change every 24 hours.

[00:40:01]>> So Turing doesn't try to break the code himself. He envisions something far more [music] powerful than a human brain.

[00:40:09]Turing creates a special machine [music] and this enables him to analyze thousands of transmissions [music] at a time.

[00:40:18]>> It's really the world's first computer and it's called the bomb.

[00:40:22]>> What Turing's created is something so technologically far ahead of its time and I think that's why we marvel at its creation is just extraordinary.

[00:40:32]On April 1st, 1941, Bletchley Park first breaks the Enigma code.

[00:40:37]>> Thanks to Turing, more than a million enemy transmissions [music] are intercepted, laying bare the position of Germany's Wolfpacks, around which over 1.2 million tons of shipping are rrooted.

[00:40:51]Britain's [music] transatlantic lifeline is open, but it doesn't last long. Germany's Enigma code gets an upgrade.

[00:41:04]>> The Germans notice that they haven't intercepted a convoy for 6 months or so.

[00:41:10]So to be on the safe side, they add an additional rotor to the Enigma.

[00:41:15]>> Enigma's code combinations increase 26 times to over 32,000 trillion, a number that even Alan Turing's proto computer cannot cope with.

[00:41:28]For the Wolfpacks, hunting season is back on.

[00:41:33]>> This Enigma blackout could not have come at a worse time because the US is about to send lots of people and lots of equipment across the Atlantic through the potentially dangerous waters where Yubot are hunting.

[00:41:48]>> In the last 6 months of 1941, Yubot sink just over 720,000 tons of Allied shipping.

[00:41:57]In the first quarter of 1942 alone, sinkings rise to 2.6 million tons. And by year's end, that figure rises to almost 8 million tons and 1,662 ships.

[00:42:13]To make matters worse, the Royal Navy's oil reserves are down to just 2 months.

[00:42:20]The Allies need another breakthrough.

[00:42:23]It comes in spectacular fashion.

[00:42:27]in Mediterranean waters off the Egyptian coast.

[00:42:30]>> In October 1942, Ubot 559 is actually hit by HMS Petard and sunk below the water line.

[00:42:41]>> While it was sinking, three Royal Navy sailors dove overboard, swam to the Yubot, went aboard it, rummaged through it. As it's sinking, the hubot suddenly rolls over and two of the sailors go down with it, sacrificing their lives.

[00:42:58]>> But it was vital because the survivor actually pulled a code book from that Ubot.

[00:43:06]And when Cheuring poured over it back at Bletchley Park, they were able to break the upgraded Enigma codes. That sacrifice was so worthwhile because soon thereafter, Bletchley Park is reading the Yubot mail again.

[00:43:22]>> Over the next year, the Germans sink only 812 ships for the loss of 242 submarines.

[00:43:32]At the same time, new weapons like the Hedgehog anti-ubmarine system and the B-24 bomber come online.

[00:43:40]>> The pendulum swings and the hunters become the hunted.

[00:43:44]Facing total annihilation, Donitz orders all his Ubot to withdraw from the North Atlantic on the 24th of May, 1943.

[00:43:54]The following month is the first in the whole war in which not a single convoy is attacked.

[00:44:01]That is what turns the tide on the Yubot. And from [music] May 1943 until the end of the conflict, the Yubot is no longer the scourge of the seven seas.

[00:44:13]Yet all this will be for Nort if the Soviets cannot win the battle for Russia.

[00:44:19]On the banks of the river Vulgar, a desperate struggle for survival is being fought out in a nondescript city whose name will echo through history.

[00:44:31]Stalinrad.