The valley below Verbier reaches 30 km up to the giant Mauvoisin dam at the head of the Mauvoisin basin — at 250 metres one of the tallest arch dams in the world. The road up the valley passes through the village of Fionnay and ends at a small mountain hotel just below the dam wall.
The lower valley is dotted with traditional Valais wooden chalets and small dairy farms; the upper reaches are wild high mountain. Several long hikes start from the dam, including the GR Tour des Combins. By car it is a long but rewarding day out from Verbier; the postal bus runs as far as Fionnay several times a day in summer.