The fortress had four gun positions, of which one of the guns is still intact. The others were dismantled in 1960s. The 38 cm calibre naval cannon is one of the largest in the world. The barrel alone weighs 110 tons, measures almost 20 m in length and has a range of up to 55 km (34 miles), which is half way to Denmark. There is the Fortress Trail in the museum, a walk to places and buildings which tell of everyday life in the fortress.