Three kilometres downstream from La Roque-Gageac, the Château de Castelnaud sits on a steep rocky promontory with commanding views across the Dordogne valley. It is one of the finest medieval military fortresses in France: substantially intact, authentically restored, and housing an outstanding museum of medieval warfare that fills the keep and courtyard with siege engines, armour, weapons, and interactive displays explaining the military technology of the 13th to 15th centuries.
The castle was at the centre of the Hundred Years' War, changing hands repeatedly between English and French forces. A walk along the ramparts gives a clear view of the strategic logic: from up here you control the river and the valley roads. The view across to the Château de Beynac — its great rival, two kilometres upstream on the north bank — is particularly striking. Castelnaud is open throughout the year and is one of the most visited historical sites in the Dordogne; arrive early in summer.