The hills and canal of Corcos Nature · Corcos del Valle, Campiña del Pisuerga, Valladolid Its 42.55 square kilometres at 789 metres combine holm oak and gall oak woods of the moorland with the plain of the Pisuerga and the course of the Canal de Castilla, which for centuries drove the flour mills of the municipal district. Photo: Mentxuwiki (CC BY-SA 4.0) What to see and do in Corcos del Valle