High on its rocky outcrop, the citadel looms over Sisteron. The keep and the rampart walk date from the 12C, but the fortifications are 16C. Interesting museum devoted to Napoleon's return from the island of Elbe and a 15C chapel adorned with modern stained-glass windows. Splendid views of the lower town, the lake formed by the dam and the impressive Rocher de la Baume.