Today's abbey is built on the remains of a Romanesque church, which was built on the ruins of a Carolingian church. Visiting the abbey, imagine the headaches and hassles the monks had when they built it. They ferried granite from across the bay and hiked it uphill.
A walk in the abbey is a one-way route through fine — but barren — Gothic rooms. A rented audioguide or English-language tour make this historic sight more meaningful. Visitors may explore the impressive church, delicate cloisters, and refectory (where the monks ate in austere silence), and then climb down into the dark, damp Romanesque foundations. A highlight is the giant tread-wheel, which six workers once powered hamster-style to haul two-ton loads of stones and supplies from the landing below. This was used until the 19th century.