The Baltic Sea anomaly is a feature visible on an indistinct sonar image taken by Peter Lindberg, Dennis Åberg and their Swedish "Ocean X" diving team while treasure hunting on the floor of the northern Baltic Sea at the center of the Gulf of Bothnia in June 2011. The team suggested their sonar image showed an object with unusual features of seemingly non-natural origin, …

The Baltic Sea Campaigns were conducted by Axis and Allied naval forces in the Baltic Sea, its coastal regions, and the Gulf of Finland during World War II.After early fighting between Polish and German forces, the main combatants were Germany and Finland, opposed by the Soviet Union. Sweden's navy and merchant fleet played important roles, and the British Royal Navy planned …