Reservoir of o Leboreiro Nature · Montederramo, Terra de Caldelas, Ourense Dammed in 1949 with a gravity dam on the río Mao, it holds some four cubic hectometres and spreads a sheet of water of about 57 hectares among the high lands of the concello, upstream of the canyon. Photo: manolofeal (CC BY-SA 3.0) What to see and do in Montederramo