A Gothic masterpiece, the cathedral was begun in 1195 and consecrated in 1324. The immense west façade features five portals, the central one of which depicts the Last Judgement and leads into five interior naves. The stained-glass windows (12C-17C) are among France's finest. The crypt is superb, as is the astronomical clock. A 396-step climb leads to the top of the north tower, from where there is a panoramic view over the town, marshlands and Auron Lake.