The Quebrada del Toro is a long, narrow valley cut through the Andes of Salta, in north-west Argentina, and the old road that follows it was a trade route for centuries. Santa Rosa de Tastil sits on a terrace above the river, at around 3,200 metres, and it was a town: a settlement of stone houses, perhaps several hundred of them, built in the fourteenth century and inhabited until shortly before the Spanish conquest. People here farmed, kept llamas and traded across the mountains, and when the Incas arrived they connected the place to their road system, the Qhapaq Nan, which was inscribed by UNESCO in 2014.
Walking through the ruins is oddly moving. The foundations of rectangular houses, packed close together and stepped up the hillside, make a pattern you can read at a glance, and the surrounding hills are a deep red and brown, dotted with tall cardon cacti. A small museum beside the site shows pottery, textiles and tools found here, and a local guide can explain how the town worked. The air is dry and thin, the sun is hard, and the wind picks up in the afternoon.
The ride up the Quebrada del Toro on Ruta 51 from Salta is one of the finest in the north of Argentina. The road follows the river, crosses it several times, and climbs through gorges of coloured rock toward the high plateau of the Puna, with the railway that carries the Tren a las Nubes visible above you in places. The tarmac is generally good, with some patchy sections, and the curves are long and open. Above Tastil, the road climbs to the pass of Abra Blanca, over four thousand metres, and the cold and thin air are noticeable.
Fuel is not available in the village. Fill up in Salta before the climb, and again in San Antonio de los Cobres, farther up the road, and carry a reserve. Altitude can cause headaches and tiredness, so take it slowly. Weather is dry for most of the year, with summer storms from December to March. Mornings are best for light and wind.