Kalvøysund fort was a German coastal fort on the island Flostaøya east of Arendal, built during WW2. Today this is a popular recreational area.
The battery was meant to cover the eastern seaward approach to Arendal, and the area was more than 10 acres large. Kalvøysund fort was one of the largest fortifications the Germans built in Southern Norway during the second World War.
The fortifications were built in 1941 and consisted of about 50 buildings and bunkers. There are four locations for cannons in the area, and the cannons who were there had a range of 11-12000 metres. Bunkers and other parts of the fortification are kept partially well, and the foundation walls from many of the buildings are still left in the landscape.
After WW2, the fort was run by the Norwegian armed forces for a while, and there were a couple of military exercises on the fort. Then the area was given to the local authorities, and it is now a popular recreational area. There is a public bathing area in Kalvøysund, and the area is open to the public.