Peñalén, mirador sobre el Arga y el Aragón Nature · Marcilla, Ribera Alta, Navarra Image of Marcilla, not of the place itself. A natural cliff 5 km from Marcilla, on the hill of Funes, located at the confluence of the Arga and Aragón rivers, with a marked trail and panoramic views of the valley. Photo: Millars (CC BY-SA 4.0) What to see and do in Marcilla