In the dying days of World War II, a German sub was reportedly sunk near the Danish coast, but the wreck was never found, leading to speculation that high-ranking Nazi officials - even possibly Adolf Hitler himself - used the high-tech vessel to escape to South America. A museum in Denmark has finally found the missing U-boat, ending this 73-year-old mystery.
The submarine was found with its nose in a hole, its rear extending from the seafloor at a 45 degree angle. Image: Sea War Museum Jutland
The German submarine was discovered under 123m of water earlier this month by an expedition from the Sea War Museum Jutland. Radar scans of the seafloor taken from the survey ship Viña show the U-boat U-3523 - an advanced Type XXI submarine - resting in an extraordinary position, with its tail-end sticking out from a hole at practically a 45 degree angle.
This is now the ninth German sub discovered by the Sea War Museum along the Danish coast, in addition to three British subs. In total, the museum has discovered 450 wrecks in the North Sea and in the Skagerrak Strait between Norway, Sweden, and the Jutland peninsula of Denmark.
According to the British navy, a B24 Liberator sunk the U-3523 on 6 May 1945 using depth charges, which are underwater explosives dropped from above. Given the timing of the incident, the U-boat was likely not on patrol, but on the run. The sinking happened a day after Nazi forces surrendered in Denmark, and just two days before the war officially ended in Europe. Fifty-three German sailors were killed in the incident, assuming its standard contingent was on board.
The U-3523 was found in the Skagerrak Strait some 16.6km northeast of Skagen. The pilot of the B24 Liberator reported a location 2km away, which may explain why the sub eluded discovery for so many years. Its unorthodox position on the seafloor may have had something to do with it as well.
Despite the British navy's report of the sinking, the inability to locate the wreck fuelled speculation that the submarine had managed to escape. Conspiracy theorists suggested the sub contained a hoard of gold, and that high ranking Nazi officers, including Hitler, made their way to Argentina.
Much of this speculation had to do with the nature of the sub itself. The German Type XXI U-boat was the Kriegsmarine's most advanced sub, and the first capable of making an extended trans-Atlantic voyage without having to resurface. Hence the unsubstantiated rumours.
A schematic of the German U-boat U-3523 overlaid with the radar image. Image: Sea War Museum Jutland
After the war, Britain, France, the United States and the Soviet Union seized a number of Type XXI U-boats for study. This directly led to the development of the Soviet Whisky class sub, which were active during the Cold War. The Germans produced 118 of these vessels, but only two entered active service, and none ever saw battle. Only one XXI remains in existence, and it's on display at the harbour outside the German Maritime Museum in Bremerhaven.
It's unlikely the U-3523 contains gold or the bodies of top Nazi officials, but we'll probably never know. As a war grave, the sub is protected from intrusive investigations. What's more, its position on the seafloor will make further study very difficult, even for a remotely operated vehicle.