Quebrada de Humahuaca follows the line of a major cultural route, the Camino Inca, along the spectacular valley of the Rio Grande, from its source in the cold high desert plateau of the High Andean lands to its confluence with the Rio Leone some 150 km to the south. The valley shows substantial evidence of its use as a major trade route over the past 10,000 years. It features visible traces of prehistoric hunter-gatherer communities, of the Inca Empire (15th to 16th centuries) and of the fight for independence in the 19th and 20th centuries.