The fort was built in 1943 by the Nazis occupying Norway during World War II as a part of the Atlantic Wall.

[1] The fort was equipped with four of the world's largest land-based guns (40.6 centimetres or 16.0 inches).

The guns were taken out of the Norwegian mobilisation plans in 1961, but are still in place and one is kept in working order for conservation purposes.

The standard shell weighed 1,030 kilograms (2,270 lb) with a range of about 43,000 metres (27 mi), while the lighter 600 kilograms (1,300 lb) shell had a range of about 56,000 metres (35 mi).

As a part of the Atlantic Wall, the fort is unique in its original set up and high degree of preservation.