Archaeologists found multiple layers of history underneath the Cathédrale St-Pierre when its foundations began to falter in 1976. Excavations have so far yielded remnants of two 4th-century Christian sanctuaries, mosaic floors from the late Roman Empire, three early churches, and an 11th-century crypt. The first Romanesque cathedral on the site was built in 1000; today audio guides in English and careful lighting help navigate the (reinforced) underground maze that remains.
Visit the Travel Talk forums for help on planning your trip