Located 25 km from Carcassonne, the chasm was discovered in 1970 by the caving club of the Aude. The gulf has impressive dimensions, 80 m wide and 250 m depth, it is known worldwide for its wealth of training, all the underground environment offers more prestigious discs, eccentrics, aragonite, draperies, columns , waterfalls ...
The variety of crystallizations is exceptional in crystals of calcite and aragonite, richly colored with metallic oxides (iron and manganese).
The Red Room, so named for the ocher bright due to the presence of iron oxide, with disks, huge platters of crystallization literally hanging from the ceiling and which can weigh several hundred pounds.
The vast underground network is traversed by an underground river whose bed is carved in marble blue. Traversing several kilometers underground, the river returned to the spotlight at the foot of the castles "Cathar" Lastours.
