Ourense - The Sil valley.
A few kms. before arriving in Ourense and coming from Ponferrada and Astorga, the Sil valley is on your right. Possibility to descend and hire a boat. Take the direction of the monastery San Estevo de Ribas de Sil.
Another short trip is out to the Monastery of Santa Maria de Real de Oseira, a 12th c. cistercian building. I didn't have the time to go here, the photo is taken from the steps in front of the San Francisco cloisters.