The narrow streets form an irregularly shaped little island, 350m long and 100m wide, linked to the mainland by two small bridges, separated by a fortified structure. This is overlooked by a belfry (1906), which has become the symbol of the town. It is encircled by sturdy ramparts, built in the 14C and added to in the 17C. Arrow slits command views of the city, including the inner harbour with its moored trawlers, and the fish market. Rue Vauban, the main street, is busy in fine weather.