The Incas built a road across the Andes, and in the north of Argentina it still runs under the hooves of mules and the boots of walkers. The Qhapaq Nan, the Great Inca Road, was a network of some 30,000 kilometres linking the empire from Colombia to Chile and Argentina, and parts of it were inscribed on the World Heritage list in 2014 across six countries. The segment of Chaupiyaco to Las Capillas, in the province of Salta, runs through the high valley of the Quebrada del Toro, one of the old routes between the Altiplano and the lowlands, and the section near Santa Rosa de Tastil follows the course used long before the Inca, by herders with llamas.
Santa Rosa de Tastil is the best-known archaeological site nearby, the remains of a town of stone houses on a terrace above the river, which flourished in the thirteenth and fourteenth centuries before the Inca arrived. Hundreds of rooms, tombs and plazas can be seen, and a small museum next to the site houses the finds. The setting is magnificent, a wide, dry valley of red and ochre hills, with cardon cactus on the slopes, and the thin air at over three thousand metres has a bright, hard clarity.
The ride up Route 51 from Salta is spectacular. The road leaves the green valley of Lerma, climbs the Quebrada del Toro beside the river with tunnels, sharp bends and steep rock walls, and then climbs further toward the high plateau, the puna, passing the railway of the Train to the Clouds. The surface is mostly paved but with sections of damage, rockfall and gravel, and the altitude brings thin air, fierce sun, and temperatures that fall sharply at night. Wind is common, and sudden storms in summer can bring floods and landslides. The dry season, from April to October, is the best time, although nights can be freezing.
Santa Rosa de Tastil is a small place, and fuel is in Salta, in the lowlands, and in San Antonio de los Cobres, farther on, so fill up beforehand and carry extra. Altitude can bring headaches, so take it slowly, drink water and chew coca leaves if locals offer them, as they do. Empanadas and humitas are the local snacks.