Older than Vesuvius. It is among the biggest of Italy, but extinct since fifty thousand years ago. The Roccamonfina volcano rises isolated between the Aurunci Mountains, in Lazio, and in Campania Felix the plain of Garigliano and the Massico massif, separating it from the Tyrrhenian Sea.

With a surface of over 1500 square kilometers, the limestone massif of Matese stretches between Molise and Campania and falls within the territory of four provinces.

It starts in the area of Frosinone from the confluence between the Liri, which first crosses Abruzzo and Lazio, and the Gari, which rises at Cassino and is often called Liri-Garigliano.