Stevns Fort is a Cold War installation on the coast in Denmark, constructed and excavated in 1953 to control the southern entry to the Baltic Sea. Its armament included two twin barrel 15cm guns, originally fitted to the German Battleship Gneisenau. The turrets of these guns weigh over 100 tonnes with the barrels a further 10 tonnes each.
Below ground, the site was excavated into the granite bedrock and mirrored so that the two halves could operate independently to provide resilience. Around 1700 metres of tunnel were excavated, 18 metres below the surface. Run by the Danish Navy, a garrison of 300 men had supplies for three months, including 80,000 litres of fuel and an artesian well. Spoil was extracted out of exits in the cliffside, which later became emergency exits.
Both original and updated fire control rooms and computers remain in situ and support facilities include dormitories, kitchens, dining facilities, air-handling and emergency power generators. The passages are largely unlined but rooms off them are constructed with an air separation from the natural rock which provided both waterproofing plus some resistance to the propagation of shock waves.
From 1984 the site beame a radar control and communications centre and many artefacts remain from this period, preserved since its closure in 2000. Above ground a NIKE anti-aircraft battery was sited here from the 1960s. This in turn became a base for the mobile HAWK anti aircraft system in 1984.
The whole site is a splendid museum and a visit is thoroughly recomended.