The “Cliffs of Perticali” are the distinctive gullies on the Tanaro River in the territory of Clavesana, recognized as a Geosite of Interest by ISPRA and included in the National Inventory of Geosites. Calanques are narrow, deep furrows along riverbanks, characterized by slopes devoid of vegetation, caused by a geomorphological phenomenon of soil erosion that occurs because of rainwater runoff on clayey rocks. The Clavesana gullies appear as deep “knife-edge” furrows, very steep and with a branching radial arrangement that runs along the Tanaro coast. Clavesana is in the middle Tanaro Valley, where the watercourse widens in a characteristic meandering pattern into a wide valley floor.