The Serpentine, (first tributary of the Ain river whose source is located a little higher) forms a small lake near the ruins of a mill. It is from a cornice …
Beautiful hiking trail, well-maintained path. The area between Grand/Petit lac Maclu and Lac d'Ilay is currently (August 2022) closed to the public (nature reserve). The route on the west side of Lac d'Ilay is unfortunately less attractive.