Mao river Nature · Montederramo, Terra de Caldelas, Ourense Image of Montederramo, not of the place itself. It rises in the sierras of the central massif, on the northern slope of the Sierra de San Mamede, and passes by the monastery before narrowing on its way to the Sil, through a valley of oak woods where mills and walls from old hydraulic works can still be seen. It flows north through places such as Sabín, Veredo, Nogueira and Pedrafita until it meets the Sil near Cristosende, between the concellos of A Teixeira and Parada de Sil. It forms a single reservoir, that of Leboreiro, with a small hydroelectric plant known as A Fábrica da Luz near the mouth, and in its final stretch it carves out one of the most impressive canyons in the province of Ourense, dropping from 860 metres at Leboreiro to 240 metres at the Sil. Photo: Gregorio Puga Bailón from A Coruña, Spain (CC BY 2.0) What to see and do in Montederramo