Proumeyssac gouffre or pit is best discovered on foot through the tunnel or by going down in the same baskets that enabled its discovery in 1907. Its forms underscored by light and sound effects, this "crystal cathedral" is guaranteed to leave an impression. The magnificent cupola (52m/171ft high and reaching 60m/97ft wide) reveals beautiful concretions. The water, which continues to seep through abundantly, adds to the numerous stalactites already in place to form four impressive petrifying fountains.