The Cathars were an alternative religious sect to Christianity, in the 13th century.   They were wiped out by a crusade instigated by the Papacy.  The old castles that defended the border between France and Aragon became their last strongholds: all fell under seige.

Queribus is the most complete and, we think, the most spectacular of the Cathar castles.

The upper part of the keep (donjon) has been rebuilt and you can go to the top for superb views.

Nearby Peyreperteuse is a large fortification of two keeps.  Ruined but still spectacular.  Some very treacherous steps to climb here.