The Ossau Valley: A Volcano's Remains, the Lacs d'Ayous and the Artouste Train

Required Activities

• Walk the classic 14 km loop from the Lac de Bious-Artigues past the six lacs d'Ayous — Roumassot, du Miey, Gentau, Castérau, Paradis and Bersau — and find the one where the north face of the Pic du Midi d'Ossau stands whole in the water; the boundary of the Pyrenees National Park is at the far end of the Gentau, so the lakes themselves are outside it

• Take the cable car up from the Lac de Fabrèges at 1,240 m, then ride the 10 km of 500 mm track to the Lac d'Artouste, looking straight down into the Soussouéou valley the whole way and through the 315 m Tunnel de l'Ours — the line was laid in 1920 to haul cement up for the dam, and only put to work carrying tourists in 1932

• Walk up to the foot of the pic and stand in the cirque de l'Embarradère, the 200-hectare hollow between the Moundelhs and Peyreget arcs that is the actual crater of the Ossau volcano — then look up and pick out the notch of the Fourche, 180 m below the summit, that separates the Grand Pic from the Petit Pic