The Sancy stratovolcano is one of the volcanic chains of the imposing Monts Dore massif. The volcanic activity of the massif began ten million years ago with vast basalt outflows, followed three million years ago by a gigantic Plinian eruption (Vesuvius like) which sent ashes 35 km around. The vacuum created underground caused the collapse of the upper Dordogne caldera and the establishment of a multitude of peripheral formations. The emergence of the Sancy stratovolcano completed this process only 250,000 years ago, hence the still vigorous relief visible in this photo.