Visible from the ridge of Puy Gros about 2,952 feet (900 metres) away, the ‘Aiguilles du Diable’ are a set of dykes with a basaltic organ structure of irregular and twisted entablatures. They are lava veins that were pushed by the pressure coming from the magma chamber and have appeared over time and through glacial erosion. They are located on the Southwest slope of Puy du Sancy, near its summit.