Fort des Dunes, Military museum and fort in Leffrinckoucke, France

Fort des Dunes is a military fort and museum in Leffrinckoucke on France's northern coast. The site features exhibitions about regional military history displayed through interactive rooms and video installations.

The fort was constructed between 1878 and 1880 as part of a defensive network protecting the Flanders region. During World War II, it served as a strategic position for German occupation forces.

The fort is maintained and interpreted by the Association Fort des Dunes, which opens it on summer weekends. German troops left murals and decorations in the magazines and barracks, still visible today. The site also holds the graves where General Janssen and officers killed on 2 June 1940 were first buried near a gun platform.

The fort is usually open to the public only on summer weekends, so plan your visit around that window. The site sits on a sandy hill about 27 m high, with the barracks and service areas recessed into the ground and covered with soil and turf. The entry tunnel is largely exposed and the dry moat and ramparts are uneven underfoot, so sturdy footwear helps.

A circuit path leads to preserved structures from the German occupation period, showing how the site was modified during wartime. These remains offer direct insight into the daily reality of that era.