Ouvrage Hackenberg is located in France

Ouvrage Hackenberg, one of the largest (a gros ouvrage) of the Maginot Line fortifications, is part of the Fortified Sector of Boulay. It is situated twenty kilometers east of Thionville, in the Moselle département, near the village of Veckring, on the Hackenberg (343 meters). It is located between gros ouvrage Billig and petit ouvrage Coucou, facing Germany. The fort occupies the wooded Hackenberg ridge. Before World War II it was considered a showpiece of French fortification technology, and was visited by British King George VI. In 1940 Hackenberg was never directly attacked, providing covering fire to neighboring positions and harassing nearby German forces. Its garrison was one of the last French units to surrender after the June 1940 armistice. In 1944, under German occupation, it was in action against American forces advancing along the Maginot Line. It resisted for three days before artillery bombardment from the rear forced the Germans to evacuate. Following World War II it became part a strongpoint meant to delay a potential advance by Soviet forces into northeastern France. Hackenberg has been preserved and operates as a museum.

• http://en.wikipedia.org/wiki/Ouvrage Hackenberg