Ouvrage Immerhof, Maginot Line fortification in Hettange-Grande, France.

Ouvrage Immerhof is a fortification built as part of the Maginot Line with four concrete blocks connected by roughly 250 meters of underground tunnels. These passages lead to quarters that housed up to 198 soldiers during its operational period.

The fort was built between 1930 and 1935 to defend the railway line between Thionville and Luxembourg. It was designed to work together with neighboring fortifications Molvange and Soetrich as part of a coordinated defense network.

The name Immerhof reflects the site's role as a defense position in the landscape. Visitors can walk through the underground spaces and see how soldiers lived and worked in these cramped quarters.

The fort is easily accessible and visitors should wear appropriate clothing as the underground spaces stay cool year-round. Guided tours are available and provide the best way to explore the site safely and learn its history.

Immerhof and Ouvrage des Sarts are the only two Maginot works built entirely in the open air and then backfilled, without tunnelling. The crew gave Immerhof its own nickname, "Le Tiburce", after Saint Tiburce. Volunteers of the association Le Tiburce have restored the generators, electrical network and ventilation, and one of the two turrets works again.