It is formed by two peaks of similar altitude, connected by a natural arch which has given the group its name (meaning "Holed Mountain" in Italian). The hole, nearly circular in shape, has a height of c. 26 m,http://www.apuanegeopark.it/schede_geositi/arco_naturale_forato.pdf while the arch itself is some 8 m thick. The arch can be seen from both Versilia and Garfagnana valleys at the two sides of the Monte Forato.
