Les Pertes de la Valserine, ENS de l'Ain

From the car park along the D1084, take a path for around 20 minutes down to the Pertes de la Valserine, where the waters of the river disappear into a bottomless abyss, only to reappear beyond a labyrinth of limestone canyons.

The Valserine is the 1st French river to be awarded the "Rivières Sauvages" label. It offers the guarantee of its great purity. Trout spawn in its waters, and reserves protect them in certain places.

The Valserine has contributed to the industrial and commercial development of Bellegarde, and has also served as a border on several occasions: between France and Savoie (1601-1760), then as a free zone (1815-1923) and as a demarcation line during the Second World War (free zone on the right bank).

Other possible starting points for the walk:
- from the Voie du Tram car park at Rougeland
- from Bellegarde town centre, taking the bypass via the Voie du Tram and then the G9.