The submarines had been carried 2,000 miles overland from Germany to attack Russian shipping during the Second World War, but were scuttled as the war neared its end. Now, more than 60 years on, explorers have located the flotilla of three submarines off the coast of Turkey.
The vessels, including one once commanded by Germany's most successful U-boat ace, formed part of the 30th Flotilla of six submarines, taken by road and river across Nazi-occupied Europe, from Germany's Baltic port at Kiel to Constanta, the Romanian Black Sea port.
They don't seem to be deep enough for the anoxic layer to have preserved the organic remains which I think starts at over 100 meters down, but they still should hold a lot of intact stuff. Be neat if they could be raised.