The Sasso Regino is a large limestone boulder that gives its name to the entire area. Before the Second World War, this area was devoid of vegetation, and from the Sasso one could enjoy a wide view over the plains of Pistoia, Prato, and Florence. There used to be the Fonte del Sasso Regino as well, a historic spring located beneath the boulder of the same name, around which some legends once circulated; unfortunately, it was buried by a landslide during the November 2023 flood.