The donjon and the covered way date back to the 12C. The fortifications erected by Jean Errard, Henri IV's engineer were reinforced by Vauban. From the citadel you have bird's eye views of the lower town and the lake of the dam (from the terrace). You also have an impressive view over the rock of la Baume ( from the Devil's sentry box). The chapel contains beautiful stained-glass windows by the master glassworker Claude Courageux.