The amazing architectural verticality of this Cathar castle, fully in tune with its surrounding mountain landscape, is most impressive. Usson Castle was built between the 11C and the 12C to control the Aude Valley, over which it enjoys a matchless view. While little remains of the original edifice, the former stables are home to the Donézan heritage centre where you can see a reconstitution of a mountain habitat and an elegant sculpture of the Lady of Usson.