Perched on a rocky outcrop at the top of Mont Ardu, the old Cathar castle of Puilaurens is now in ruins. Listed as a Historical Monument since August 12, 1902, they extend 0.62 miles (1 km) southwest of the town of Lapradelle in the Aude department. Composed of a backyard, upper courtyard, and a fortified enclosure that follows the contour of the rock base created by Mont Ardu, the Château de Puilaurens is the archetype of the medieval military mountain citadel. Access to the castle is via a chicane ramp arranged in the rock to the southwest that is then bordered by nine walls.