The Quebrada de Humahuaca is a roughly 155 km high valley in Jujuy Province, traversed by the Río Grande flowing north to south. Its rock walls glow red, ochre, yellow, and violet, due to exposed strata from many geological eras. For approx. 10,000 years, humans used the valley as a trade route, later also the Incas; in 2003, UNESCO declared the Quebrada a World Heritage cultural landscape.Along the road are strung small towns: Purmamarca with the Cerro de los Siete Colores, Maimará with the "Paleta del Pintor", Tilcara with the reconstructed pre-Hispanic mountain fortress Pucará, and Humahuaca at the northern end, from where you drive to the Serranía de Hornocal with its "14 Colors". The climate is dry and windy. The valley is high; allow time for acclimatization.