Situated on the slopes of the Pratomagno, between the stream Resco north-west and the stream Ciuffenna south-east, on a surface belonging to four different municipalities, the protected area aims at preserving an important geomorphological relief. The area's geological nature - river and lake sediments with different particle sizes and conglomerates - allowed the development of particular erosion forms such as badlands, crags and stacks isolated by erosion: therefore it represents a typical morphology of great interest from the landscape and environmental point of view.