The castle lies within the fortifications of the town and access to the ramparts can be gained through the castle. Dating from the 12th century, it belonged to the Counts of Trencavel, and was built to replace an earlier structure on the eastern extremity of the rocky outcrop. Some vestiges of the Trencavel castle can be seen: the crenellated parapet of the upper floor and the chapel apse. New defences were added in the 13th century as well as more opulent rooms such as a banqueting hall. Bases of a stone colonnade and a transomed window with tracery work can still be sen. The castle houses a lapidary museum and a permanent exhibition of the restoration of the fortifications of the town in the 19th century by Viollet-le-Duc. Opening hours are 9.30am - 6.30pm April to Spetember and 9.30am - 5pm October to March.