It is located inside a limestone mountain named Cap de la Lesse between the Vicdessos and Ariège valley.

There is also an intermediate level at 600 m (2,000 ft) which has much fewer passages but is the entrance section of the Lombrives show cave.

To make this size a little more understandable the guides compare it with the Cathedral of Notre-Dame in Paris, which would fit into the chamber.

The earliest excavations by Félix Régnault took place in the late 19th century and confirmed human occupation during the Neolithic.

Today the cave is a tourist attraction, offering a selection of guided tours lasting between two and five hours.