In which sea would you find the island of Bornholm?

Bornholm is a Danish island in the Baltic Sea, to the east of the rest of Denmark, south of Sweden, northeast of Germany and north of the westernmost part of Poland. The main industries on the island include, dairy farming, and arts and crafts such as glass production and pottery using locally worked clay. Tourism is important during the summer. Bornholm's geography as an island and moderate climate makes Bornholm an ideal location for sailing and other water-based sports. Bornholm has been fought over for centuries. It has usually been ruled by Denmark, but also by Lubeck and Sweden.

Bornholm, as a part of Denmark, was captured by Germany on 10 April 1940, and served as a lookout post and listening station during the war, as it was a part of the Eastern Front. These remnants of Nazi rule have since fallen into disrepair and are mostly regarded today as historical curiosities. Many tourists visit the ruins each year, however, providing supplemental income to the tourist industry.

Bornholm was heavily bombarded by the Soviet Air Force in May 1945. After the evacuation of their forces from Bornholm, the Soviets took the position that the stationing of foreign troops on Bornholm would be considered a declaration of war against the Soviet Union, and that Denmark should keep troops on it at all times to protect it from such foreign aggression. This policy remained in force after NATO was formed, with Denmark as a founding member.