During World War II, the Bunkerdorp Schlei was constructed, which consisted of bunkers, radar installations, anti-aircraft guns and camouflaged barracks. High up on the dune is the unique Wassermann bunker. Set up as a museum, the Seeburg bunker served as a communications centre during the war. Data from radar and radio signals were collected here and passed on to the Luftwaffe, which tried to intercept spotted Allied aircraft with fighters.