The Batterie de l'Éperon, located at the northern tip of the Moselle loop, is a unique site housing, in one location, a number of components of the so-called “Séré de Rivières” defence system. The closest fort to the site of the Battle of Grand Couronné, the battery’s job was to protect key communication posts and prevent the enemy entering the Forest of Haye.
The site is home to a technical masterpiece of the late 19th century: the last remaining Galopin retractable gun turret (1890 model) – a vast steel construction that is the only one of its type in the world and is impressive for its size and its technology.
The battery was open to the public in 2007. A local association, known as Sauvegarde du Patrimoine Fortifié de Frouard, runs guided tours of the site, which it preserves and maintains.