View from Mirador de Antahuilque in E (upstream) direction. The Colca Valley has been inhabited since pre-Incan times, so that ancient terraced farmlands are characteristic features of the valley. These terraces overlay a complex and weird-looking topography, which is the result of the interaction of volcanic processes, earthquakes, landslides, lake formation, and erosion by the Río Colca. The area has been declared a UNESCO Global Geopark in 2019.