The Selva de Oza is a large tract of beech and silver fir forest in the upper Hecho Valley, roughly 14 km north of the village. The river Aragón Subordán runs through it, cold and fast and swimmable in summer (just), and the forest is old enough to feel properly wild — tall trees closing over the road, roe deer visible at dusk, the mountains appearing above the canopy.
The main car park and trailhead sits at the edge of the forest. From here, several marked trails head up into the mountains, including a connection to the GR-11 long-distance trail. A shorter loop through the forest floor, staying close to the river, takes about two hours and requires no special preparation. This is one of the finest forest landscapes in the Aragonese Pyrenees.