The La Muela viewpoint Nature · Castronuño, Tierra del Vino, Valladolid From this height one commands the great meander of the Duero that gives the municipality the nickname of the Gran Florida del Duero; at its foot lies the San José reservoir, over a municipal district of 124 square kilometres. Photo: SGGREDIAGA (CC BY-SA 4.0) What to see and do in Castronuño