This majestic and impregnable fortress, perched on a volcanic vent, retains imposing vestiges attesting to its defensive might of yesteryear. Sold as a national property during the Revolution, the fortress served as a stone quarry until Prince Jules de Polignac, Minister of Charles X, bought it and saved it from ruin. It is fascinating to visit, from the rampart walk and castle chapel to the Romanesque church and reconstituted medieval weapons. The 32m-high keep commands sweeping views.