The four Lacs de Laffrey - Lac Mort, Lac de Laffrey, the largest (3km), Lac de Petichet and Lac de Pierre-Châtel - were formed by glaciers. Between Trièves and Valbonnais, they are part of a landscape of moraine hills where forests alternate with fields, against the backdrop of the mountains of Oisans and Vercors. The lakes are often frozen over in winter (the name "Laffrey" refers to the harsh climate), but in the summer season swimming, angling and water sports are available.