From Rifugio Fratelli Calvi (2,050 m), take the comfortable trail that skirts Lago di Fregabolgia, crossing the top of the dam and continuing along the bank in an open and evocative environment. A little further on, the path leaves the dirt road coming from Carona and descends to cross the stream, entering the Valle dei Frati area.
Briefly ascend the opposite slope and continue almost level, passing the Dosso dei Signori, the junction with path 247 which descends towards Pagliari. The trail continues, crossing increasingly wooded areas until it reaches Lake Sardegnana (1,735 m). Here, cross the dam and begin a climb through the woods, with numerous switchbacks gradually regaining elevation, passing by the ranger's house.
After reaching an altitude of approximately 1,900 meters, the trail continues with a nearly flat scenic section, then crosses a vertical rocky strip without particular difficulty, thanks to passages carved into the rock and small suspension bridges. Having passed this more dramatic section, you will reach a fork near an ENEL structure; here, ignore trail 211 which descends to Carona and continue straight ahead.
The path then climbs back up towards Lake Marcio, which is skirted along the western shore to the dam. After crossing it, you briefly descend towards Lake delle Casere, crossing a small bridge, and then climb the last few meters that lead to the Laghi Gemelli refuge (1,961 m). This stage, rich in lakes, hydroelectric works, and spectacular passages, represents one of the most varied and fascinating sections of the entire itinerary in the upper Val Brembana.
