The structure of the Colli Albani, about 20 km south of Rome, is the southernmost of a chain of volcanoes, which runs along the Tyrrhenian coast of the Lazio region. The evolution of volcanism in this area is closely linked to the distensional tectonics affecting the western margin of the Apennine chain during the last two million years.
The Colli Albani represent a complex central apparatus, the result of predominantly explosive activity alternating with long phases of inactivity. The morphology resembles that of Somma-Vesuvius, with an edge enclosing a flat area about 8 km in diameter, within which is another volcano. The products of older activity form the outer rim of the Monti Tuscolani and Artemisio. Within this semi-circular structure rises then the most recent volcano, the Faete cone. Standing 932 m high, it slopes toward the southwest, where it is interrupted by the craters that now host Lake Albano and Lake Nemi.
The eruptive activity began 600,000 years ago and continued until at least 20,000 years ago. At present this volcanic complex is considered quiescent, still presenting evidence of hydrothermal and seismic activity