In the year 2000, the Danish finally declassified information about an underground fort in Rødvig, an hour and a half south of Copenhagen. People turned up from near and far to explore the huge, mysterious military structure under the white cliffs at Stevn, which had protected Denmark and monitored the Baltic Sea for vessels from the Soviet bloc for over 40 years. Stevnsfort was one of NATO’s first lines of defence from the east and would have been on the front lines had war broken out. Some of the most eager early visitors were former Stevnsfort military personnel who could finally explore areas of the 1.8-kilometre tunnel system that had previously been strictly out of bounds.