Northeast of Madrid near Monte Perdido, the Parque Nacional de Ordesa is well known for its limestone Pyrenees peaks and glacial cirques. There is a popular section of the G11 that ascends up to Rifugio de Goriz near Monte Perdido. Another popular but challenging hike runs up Valle de Ordesa to the Circo de Soaso that contains the scenic Cola del Caballo waterfall.
The main base village for exploring the Parque Nacional de Ordesa is Torla. Keep in mind that there are very limiting restrictions on camping within the park.
Overall, Parque Nacional de Ordesa is the 19th most popular hiking trail of all 21 hikes in Spain.