Gun battery Marka was established by the German army in May 1942, located south of the air base and forming part of fortress Lister. The guns had a calibre of 150 mm. and all six were mounted in open ring positions. Their range was 22 km. and behind each gun bunkers for ammunition (R607) and crew (R501) were constructed. In the centre was a large command bunker disguised as a house, with painted windows and equipped with an artificial roof. After the war, the gun battery was decommissioned and the Norwegian Air Force took over the facility, using it as a training area until as late as 2007.