This understated cathedral was begun in 1075 and largely rebuilt in the 13th century. The free-standing church tower went up in the 15th century; the spire dates from the 19th century, when its predecessor famously toppled over. Inside, three storeys of beautiful arches sweep upwards and Romanesque carvings are dotted around. Interesting features to track down include a smudgy stained-glass window added by artist Marc Chagall in 1978 and a glassed-over section of Roman mosaic flooring.
Just off the left nave is the treasury where heaps of church plates and an interesting collection of 13th-century oak chests are displayed. The peaceful cloisters are home to a worthwhile gift shop and an excellent cafe, all the profits from which go to the upkeep of the cathedral.