Mountain range of Guara (vertiente Somontano) Nature · Bierge, Somontano de Barbastro, Huesca Southern slope of the Parque Natural de la Sierra y los Cañones de Guara, in the Somontano de Barbastro (Huesca), with more than 60 caves of prehistoric rock art declared a World Heritage Site. The park, created on 27 December 1990, covers 47,453 hectares between 430 and 2,077 metres at the Guara peak, and is crossed by the Alcanadre, Flumen, Guatizalema, Vero and Mascún rivers. On this slope, Mediterranean holm oak forest predominates, with Scots pine in the higher areas, and it preserves Upper Palaeolithic rock paintings such as those of the Fuente del Trucho. Photo: Wikipedia / Wikimedia Commons (CC BY-SA) What to see and do in Bierge