This Gothic cathedral and its stately 68m-high bell tower dominate Auxerre's skyline. The choir, ambulatory and some of the vivid stained-glass windows date from the 1200s. The 11th-century Romanesque crypt is ornamented with remarkable frescoes, including a scene of Christ à Cheval (Christ on Horseback; late 11th century) unlike any other known in Western art. There's usually an hour-long son et lumière (sound-and-light show; €5) in summer.