Built in 1952–53, this complex of gun emplacements dug into the Langeland fields was designed to delay an assumed Warsaw Pact invasion if the Cold War turned hot. Themed exhibitions within various bunkers add context: those on spying and shell-loading are especially gripping. Adding to the experience, you can board Denmark's last submarine (decommissioned in 2004 and now sitting in a field), explore a minesweeper and peep inside fighter planes, comparing a Soviet MiG-23 with a NATO Draken A-005.
Exhibits are predominantly in Danish but with English and German summaries and plenty of video footage that is self-explanatory. To see everything involves a walk of about 2km, so you’ll need at least a couple of hours to do the place justice, plus an umbrella on rainy days.
The entrance is 3.3km east of Bagenkop, 750m from the Vognsbjergvej stop for bus 912.