Montpellier-le-Vieux is a rocky chaos ruiniform on the Causse Black, bordered on the south by the Dourbie Gorges, north-east of Millau, quite near the famous bridge, the town of La Roque-Sainte-Marguerite.
The rock is dolomite. Chaos covers 120 ha.
The imagination of the visitor sees similarities in rocks with ruined fortifications and give them names reminiscent of mythology. Everyone wants to be photographed under the gate of Mycenae, a large stone arch.
The shepherds called Lo Clapas Viel (The old pile of stone, in Occitan). He became Montpellier-le-Vieux when Edward Martel explored in 1883-1884 as the "Lo Clapas" is the nickname that familiar Montpellier give their city with reference to the old center of limestone.