Lac d'Artouste is a lake in Pyrénées-Atlantiques, France in the region of Nouvelle Aquitaine. At an elevation of 1997 m, its surface area is 0.56 km². It is the final destination of the Petit train d'Artouste, a narrow gauge tourist railway that can be seen in the background. The line was originally constructed for the Compagnie des Chemins de Fer du Midi (CFM), the then main line railway operator in the area to the north of the Pyrenees. As part of a program of electrifying these lines, the CFM constructed a series of hydro-electric power stations in the valley of the Ossau between the years 1920 and 1932. Significant civil engineering works were required in order to provide access to these works, and included the line now used by the petit train. Once this work was finished, the CFM recognised the tourist potential of the line, and the first tourist trains were run. Today the petit train is reached by a télécabine from a lower station at Artouste-Fabrèges, on the Lac de Fabrèges in the valley of the Gave du Brousset. This lower station is at an altitude of 1,240 m (4,068 ft) and accessible by road. The télécabine climbs to an upper station (known as Ossau2000) at an altitude of 1,920 m (6,299 ft), where passengers change to the petit train. After leaving Ossau2000, the line runs through a 315 m (1,033 ft) tunnel, crossing under the ridge to reach a point high above the valley of the Gave de Soussouéou, another of the Gave d'Ossau's tributaries. From here the line runs along a twisting and vertiginous ledge above that valley until it reaches the dam of the Lac d'Artouste.