Built between the 10C and 12C, this abbey constitutes an impressive complex with a military appearance, and is one of the major examples of the first Romanesque art in France. One of the towers was raised by a two-storey bell tower with a spire in the late 11C. Adjacent to the church, the abbey buildings are organised around the cloister, while the late 15C abbot's lodgings are set slightly apart. The crypt and its deep well are also worth a look.