Mount Vesuvius

It is a volcanic complex that includes Vesuvius and Monte Somma.

An excerpt from the article 19 facts about Mount Vesuvius
In the caldera of Monte Somma, which is a hollow in the top of the volcano, grew the cone of Vesuvius. From Monte Somma comes the term volcanic soma - the remnant of the caldera of a former stratovolcano, within which rose a new one, which is usually more prominent than the caldera.