The lake of Aydat is the largest natural lake in Auvergne. It is a volcanic dam lake. The emergence of the lava flow (the cheyre), 6 km long, from the Puy de la Vache and the Puy de Lassolas blocked the river of the Veyre and stopped the flow of water thereby creating a natural reservoir.
The island near the north bank is called Saint Sidoine, in memory of the Bishop Sidonius Apollinaris who had a Roman villa on the edge of the lake. Located in a remarkable wooded setting the environment of the lake favours pleasant strolls (the lake has a perimeter of 5.5 km).