Built in 1549, the citadel was enlarged over the years. The double walls, powerful bastions and outhouses bear the stamp of Vauban, who stayed here in 1683, 1687 and in 1689. Abandoned by the army, it was sold in 1960 to private owners. The Historical Museum is now housed in the casemates. Note the circular powder magazine, the large arsenal, where exhibitions are held, and the dungeons. The Bastion de la Mer and Bastion du Dauphin afford remarkable views.