MV Wilhelm Gustloff was a German military transport ship, sunk on 30 January 1945 by Soviet submarine S-13 in the Baltic Sea while evacuating civilians and military personnel from East Prussia and the German-occupied Baltic states, and German military personnel from Gotenhafen (Gdynia), as the Red Army advanced. By one estimate, 9,343 people died, making its sinking the deadliest maritime disaster in modern history.