visitor centre Jul-Aug: Tue and Fri 10.30am; rest of year: Tue 10.30am
They date back to the early 17C, but were altered by Vauban. In order to reinforce the defensive vocation of the Rochefort naval facilities created by Colbert en 1666, Vauban came to inspect the island in 1674. He completed the fortification of St-Martin-de-Ré in 1692. The surrounding wall has two monumental gates, Porte Thoiras to the east and Porte des Campani to the west, preceded by semi-circular spaces with guardrooms on the inner side.