Ouvrage Galgenberg, Military fortification and museum in Cattenom, France

Ouvrage Galgenberg is an underground military fortification spread across multiple blocks within the forest, accessible through two entrances on its eastern side. The complex features interconnected tunnels, ammunition storage, generators, and other operational structures built before World War II.

Surveyed by CORF in 1930, the ouvrage was built from 1931 by contractor Verdun-Fortifications and became operational in 1935 at a cost of 48 million francs. In June 1940 it fired on German infiltrators and stayed in place until the Thionville positions surrendered on 30 June. In the 1950s it was nominated as a communications station alongside Rochonvillers, Soetrich and Molvange.

The fortification reveals how soldiers lived and worked in the 1930s, with sleeping quarters, kitchens, and offices still visible throughout the complex. These spaces show visitors what daily life was like inside an underground military stronghold.

The site is well connected by walking paths and can be explored on foot, with underground areas remaining cool and damp year-round. Visitors should wear sturdy shoes and expect uneven surfaces and narrow passages when moving through the tunnels.

The ouvrage's electrical plant held four diesel generator sets, each pairing an SGCM GVU 42 engine of 150 horsepower at 375 rpm with an alternator, plus a small CLM 1 PJ 65 auxiliary of 8 horsepower at 1,000 rpm for emergency lighting and pneumatic starting. Engines were cooled by circulating water. The fort also had a small M1 main magazine compared with other gros ouvrages.