Tucked into the sleepy village of Montségur, this small museum contains a collection of Cathar relics, models of siege weapons and visual displays of what the town's castrum would have looked like during its glory days in 1240 (rather impressive). There's also a pair of skeletons found buried together who were likely slain during the town's destruction in 1244.
The museum is well signposted in the village, roughly 1.3km from the hilltop castle.