This pretty lake lies among the verdant hills of the Bas-Dauphiné, in an elongated depression originally formed by a glacier. Its emerald waters attract a lot of visitors in summer. In the southern part of the lake there lie submerged two sites of great archaeological interest: the Station des Baigneurs, a neolithic agricultural village, and the Site de Colletière, currently sunk beneath 6m of water, which is a fortified settlement that was established in the late 10C.