From the Sillaro Valley to Brisighella, in the Lamone Valley, the Romagna Hills intersect through a spectacularly recognizable silver gray ridge at first sight, which suddenly intersects the gentle hillside features, giving a unique aspect to the landscape. The protrusion, the longest chalky inscription in Italy, is 25 km long and has an average width of 1.5 km. The area is characterized by exotic forms of karst, which include dolphins, blind valleys and numerous caves, including many "cliff".