Rebuilt in the 14th and 15th centuries to protect Brittany from invasion, the fairy-tale, 11th-century Château de Vitré—shaped in an imposing triangle with fat, round towers—proved to be one of the province's most successful fortresses: during the Hundred Years' War (1337–1453) the English repeatedly failed to take it, even when they occupied the rest of the town. It's a splendid sight, especially from the vantage point of Rue de Fougères across the river valley below. Time, not foreigners, came closest to ravaging the castle, which has been heavily though tastefully restored during the past century.
The Hôtel de Ville (town hall), however, is an unfortunate 1913 accretion to the castle courtyard. Visit the wing to the left of the entrance, beginning with the Tour St-Laurent and its museum, which contains 15th- and 16th-century sculptures, Aubusson tapestries, and engravings. Continue along the walls via the Tour de l'Argenterie—which contains a macabre collection of stuffed frogs and reptiles preserved in glass jars—to the Tour de l'Oratoire (Oratory Tower).