Advanced-model (Type XXIII) U-boat that sank the last vessels of the U-boat campaign in the Firth of Forth in Scotland on 7 May 1945. Type XXIII boats later served in the Bundesmarine.

As George Dvorsky at Gizmodo reports, U-3523 was a type XXI U-boat, the Third Reich’s most advanced long-range submarine. Some researchers have speculated that the wreck could have been used to ...