Vannes is one of the best-preserved medieval towns in Brittany, ringed by ramparts that drop down to formal gardens along the river Marle. The old town inside the walls is a tangle of half-timbered houses, cobbled lanes, and small squares, centred on the Cathédrale Saint-Pierre with its mix of Romanesque and Gothic stonework.
The town sits at the head of the Gulf of Morbihan, a vast inland sea scattered with islands — boats leave from the port for day trips to the Île-aux-Moines and the Île d'Arz, or you can explore the gulf by kayak. The Wednesday and Saturday morning market on the Place des Lices is one of the liveliest in the region, with Breton produce, crêpes, cider, and local oysters from the gulf.
Vannes makes a good base for exploring southern Brittany: the standing stones at Carnac are half an hour to the west, the walled citadel of Concarneau an hour further, and the Quiberon peninsula — with its wild coast and ferries to Belle-Île — is within easy reach.