Fort du Mont Bart is located to the south of Montbéliard, France. It was built between November 1875 and July 1878 as part of the Séré de Rivières system of fortifications. The fort overlooks the valleys of the Doubs and the Allan at an elevation of 497 metres (1,631 ft), standing to the south and rear of the fortified region of Belfort and in control of the road to Besançon. The fort was intended to augment the Belfort fortifications and to prevent an enemy from bypassing them. The most striking feature of the Fort du Mont Bart is its "interior street", originally constructed in the open air as a sunken court, then covered before World War I with reinforced concrete.