The Peñas de Cervera Nature · Espinosa de Cervera, Arlanza, Burgos Image of Espinosa de Cervera, not of the place itself. This limestone ridge separates the valley of the Arlanza from the lands of the Duero and reaches heights close to twelve hundred metres. Its crests and rock faces, with juniper and gall oak, serve as a refuge for cliff-nesting raptors. Photo: Luis Rogelio HM (CC BY-SA 2.0) What to see and do in Espinosa de Cervera