The Quebrada de Humahuaca is a deep valley that runs from the border of Bolivia to Jujuy, for a total of about 150 km traveled by the Rio Grande. It starts north and descends towards the south to Jujuy. It is the most simple route and has been used since pre-Columbian times. The gorge has a unique natural beauty despite the aridity and cultural heritage( that is of great value) and therefore was named a UNESCO Cultural and Natural Heritage Site in July of 2003. My favorite places in the gorge are Purmamarca, with the Cerro de los Siete Colores, Tilcara and Humahuaca.