Begun in 1434, this cathedral wasn’t finished until the late 19th century. Still, it managed to remain architecturally harmonious—a rare feat. Two square towers dominate the facade; more impressive is the 100m-long (328-ft.) interior. Its pièce de résistance is the Renaissance tomb of François II, duc de Bretagne, and his second wife, Marguerite de Foix. The couple were the parents of Anne de Bretagne, who commissioned sculptor Michel Colombe to create their final resting place. White walls and pillars contrast with the rich colors of the stained-glass windows; helpful signs explain the significance of most objects.