The mass graves of La Pedraja Historical milestone · Villafranca Montes de Oca, Montes de Oca, Burgos In the hills of La Pedraja those repressed in the first months of the Civil War were buried clandestinely. Two graves exhumed in 2010 and 2011 yielded 135 bodies, of which only fifteen could be identified. 1936 Photo: KRLS (CC BY-SA 4.0) What to see and do in Villafranca Montes de Oca