The world's biggest red-brick church, this formidable cathedral looks outwardly more like a castle. Indeed, started in 1282, it was partly conceived to impose the power of Catholicism following the 13th-century anti-Cathar crusades. Inside, 15th-century (and later) frescoes cover the walls, explained in a multilingual audioguide that's included in the fee should you choose to visit the fabulously carved Gothic choir.
The apocalyptic Last Judgment fresco beneath the huge organ (painted 1474–84) depicts horned demons cranking wheels with tormented victims attached, souls of the unrepentant tied to the Earth in agony, while the faithful stand awestruck and naked with chests modestly obscured by well-placed prayer books.
On the right as you enter the choir is a chapel to the cathedral's namesake saint (martyred in 223). Legends state that pious Cécile, victim of a forced marriage, converted first her husband, then her jailer, to Christianity. The three first attempts to behead Cécile failed, hence the neck scars on the unnervingly realistic statue in the chapel.
The treasury houses a superb collection of ceremonial and ritual objects from the 13th to 19th centuries.
