Denmark has a unique position of huge strategic importance. If you want to enter or exit the Baltic Sea you have to go through the Danish waters – unless you have control of northern Germany in which case you can use the Kieler Canal which connects the Baltic Sea and the North Sea. The passage through the Danish waters are regulated and the main shipping lanes are international waters despite they are only a few miles from the shores of Denmark.
The passage through the Danish waters was of the utmost importance during the cold war – since the main fleet of the Soviet Union were located in Saint Petersburg – and the only way it could go into the Atlantic Ocean were by passing close by the Danish shores. Obviously it was certain the Danish waters would stay open in case of hostilities between the Soviet Union and NATO. There were plans to actually mine the Danish sounds to prevent the Soviet fleet to enter the Atlantic Ocean in case of a crisis – obviously it would be possible for the Soviet to try to sweep the mines so the fleet could escape the Baltic Sea and go into the Atlantic.
To prevent the Soviet Union to sweep the mines in the Danish waters there was built two forts at strategic positions where they could protect the mine fields which were blocking the Danish waters. One is at Stevns near the cliffs of Stevns which is actually a UNESCO world heritage. The other fort was at Langeland and it should protect the mine field which would block Great Belt and stop the Soviet Navy.
The fort is no longer in use and it has been turned into a museum you can go and visit for a day to see the old bunkers. The fort was under the control of the navy and the armament of the fort was bigger than any actual ship in the navy – despite this the navy wasn’t too happy with the forts – they would like to have some bigger ships instead so their personal could sail around instead of staying at land. But the armament of the fort was comparable to a cruiser – and the Danish navy hasn’t had any ships bigger than a frigate for a very long time.
The museum is located in the old bunkers which used to house the men who were operating the fort during the cold war. You can go down in the different bunkers and get a feel of how the staff lived. One of the bunkers is in the operations bunker and it is set up in the way it used to be during the operation of the fort. The other bunkers have different museums about spies during the cold war and the Danish volunteer defense force.
In addition to the bunkers you can go to the and see the last submarine which were in active service in the Danish navy – it has ended its day on land on the grounds of the old fort. It interesting to go inside to see just how small the old submarines actually were – it was for people suffering from claustrophobia. Another place have a fighter jet in an hangar and there is also a mine sweeper on display so you can get an idea of what these vessels looked like if you like me has never served in the navy.