Pentes River Valley Nature · A Gudiña, Viana, Ourense Image of A Gudiña, not of the place itself. A deeply cut valley in the south-east of the municipality, with a drop of some four hundred metres from the hamlet of Barxa down to the riverbed; at its bottom the Roman tunnel and the old tin mines survive. Photo: Teixuga (CC BY-SA 4.0) What to see and do in A Gudiña