The pass between Valtellina and Val Brembana is called Passo San Marco (1,992 m a.s.l.) because its construction was commissioned by the Republic of Venice in the 16th century to promote trade with the Grisons.
The climb starts in the center of Morbegno and passes through Arzo and Valle - Campoerbolo, the Orobie hamlets. The first 10 km are steady and shaded. The effort increases after Albaredo per San Marco, the last village and the last fountain. 6 km with a gradient between 8% and 10%. The forest ends, and the pasture altitude begins, marked by mountain huts and cowbells. The Albaredo valley is the home of Bitto cheese production. The flat section leads to the final and challenging 3 km climb. The finish is at 1,992 m a.s.l.
The descent back to the starting point, on the other hand, is really long.
The Giro d'Italia passed over San Marco in the years 1986, 1987, 1988, and 2007.