The Route to the Clouds covers 168km between Salta and San Antonio de los Cobres. It first follows the verdant and steep-sided valley of Río Toro, then rises in the arid, wild and multi-coloured Quebrada del Toro. Going via Santa Rosa de Tastil, which is presided over by the ruins of a pre-Inca village, the road then crosses ever-more desolate landscapes, which are typical of the altiplano, and comes to the village of San Antonio de los Cobres (3 775m). The last part (20km) leads to the La Polvorilla viaduct.