The largest and highest of the ring of 19 forts built to defend Verdun, Fort de Douaumont was captured by the Germans early in the 1916 battle and became a symbol of the struggle. It changed hands by stealth, not assault: when it was retaken in October 1916 by Moroccan troops, a key chapter of the battle was closed.
The fort can be explored on a self-guided visit. Its dark, damp corridors, gun turrets, and casemates convey the claustrophobic conditions of trench warfare better than any museum. The 155mm gun turret still works mechanically. A memorial wall lists the names of the 679 German soldiers killed in a single ammunition explosion inside the fort in May 1916. Allow an hour and a half.