La Grotte de Villars is of both geologic and prehistoric interest.
An underground river carved out immense caves linked by tunnels. There, water infiltrations created an incredibly beautiful natural setting. All types of concretions are present: calcite flows, thin stalactites, rimstone dams, translucent draperies and countless stalagmites. A spectacular sound and light show demonstrates the formation of the caves.
The prehistoric part of the cave features 17,000 year old cave paintings. Some of these, such as the horse rotunda, are covered with a thin layer of calcite that lends them a curious blue colour