The Grands Causses are several limestone plateaus at an altitude between 700 and 1200 m asl, separated by river valleys. It is bordered by the Aubrac to the north, the Cévennes to the east, the Languedoc to the south, and the Lévézou to the west. As a geographic region, its extent does not follow political borders and belongs to two different régions: Midi-Pyrénées and Languedoc-Roussillon, which are both part of the new region Occitanie. There are seven different plateaus, which are:
The whole area is composed of karstified limestone. The quantity and size of the karst features is extraordinary. This is the cradle of modern speleology, as this was the holiday destination of E. A. Martel who visited his first caves here during his summer holidays. He even developed Aven Armand as a show cave, which was discovered by the blacksmith Louis Armand. When he started his caving expeditions, Louis Armand built the required tools and ladders. He also accompanied him in numerous caving expeditions. This is definitely the most spectacular show cave in this area, as it is not only a beautiful cave, it is also entered with a funicular.