The "Balza dell'Aquila" owes its name to a pair of birds of prey that have always nested in the cliffs of the gorge. The geographical name is Fosso dell'Insollio.
From the Hermitage of Fonte Avellana head to the main road leading to Frontone, then continue towards Mount Catria. At 1150 m you reach a watershed of red rocks from which you can go downhill along the stream;  eventually you get close to the first jump of the gorge. It is a picturesque gorge, probably one of the most beautiful gorges of the Northern side of the Appenines in Umbria and Marche area. From February 1 to August 31 it is banned to reach this place, due to the nesting of the Golden Eagle.