Middelgrundsfortet
Middelgrundsfortet (lit. 'Fort Middle Ground'), known as Ungdomsøen (The Youth Island) since 2015, is a sea fort located on an artificial island in the Øresund between Copenhagen and Malmö. The fortress is constructed at a point where the seabed is 7 meters below the water surface at the northern meeting point of the straits Kongedybet and Hollænderdybet.