Etna was formed over the ages with a process of construction and destruction that began around 570,000 years ago, in the Quaternary period. In its place, there was probably a large gulf. Etna is an active volcano. Unlike Stromboli, which is in constant activity, and Vesuvius, which alternates periods of quiescence with periods of paroxysmal activity, this volcano always appears to be dominated by a plume of smoke.