Soviet submarine S-2
S-2 was a Soviet S-class submarine. In early 1940, it entered Swedish territorial waters in the Sea of Åland where it hit a Swedish naval mine, and sank on January 2, 1940 with the loss of all 50 crew members. Wreck discovery. A search for the submarine wreck was begun in April 1999 by a team of divers from Sweden and Åland. According to the Military Archives of Sweden, the submarine hit the mine in Swedish territorial waters, but the Finnish archives specify the sinking occurred on Finnish territorial waters. The uncertainty of position necessitated a  prolonged search. The diving team finally discovered the wreck inside Swedish territorial waters. One member of the diving team, Ingvald Eckerman, is a grandson of J. A. Eckerman who, as the lighthouse-keeper of the lighthouse at Märket, witnessed the submarine sinking in 1940. The wreck was emptied of munitions during the summer of 2012.