This circuit starts in the hamlet of Coldipeccio, where the uphill path n. 6 gradually unveils a lovely vista over the Valley of the Prisons, which was eroded by the homonymous brook; the gorge is covered with woods and features imposing blocks of massive limestone. Keeping the same height, walk on 2.5 km, as far as S. Giglio Spring, an important field of ammonites. The trail goes on along shady areas, and after one km it leads you to the entrance of path n. 22, on your left. This path goes steeply downhill and hikers may be disorientated, owing to the thick vegetation of brooms and brambles. Walk on to the left, along the bottom of the vale and the brook; go past a huge limestone block called "Devil's Shoe", go across a narrow gallery, which was dug for the aqueduct; after about one km, on the left, a small cattle track will lead you to the hamlet of Pascelupo; from here, go back to the starting point.