Vauban built several citadels all around France , there is one in Besançon (one of the most beautiful landmark of my city ) and also one in Belle Ile en Mer .The citadel dominates the port of Le Palais , the main city of the island. Displayed on ten hectares, its four kilometres of bulwarks preserve the memory of ten centuries during which formed.Now private property, it has been fully restored , you can visit it and stay because there is a hôtel inside, the first museum hôtel in France ! We enjoyed the visit !