Mount Etna erupting in 2013, Sicily, Italy

A sizzling summit hides in the clouds

Seen here with its explosive summit socked away in the clouds, Mount Etna towers over the Italian isle of Sicily as the tallest volcano in Europe—and maybe the crankiest, given its near-constant eruptions. The island peak has been highly active for perhaps half a million years and can still be counted on for a spectacular eruption every few years. This photograph shows Etna erupting in 2013.

Well over twice the height of Vesuvius — the mainland mount that flattened Pompeii two millennia ago — Etna has an even older reputation as a hothead. Its written history goes back as far as 1500 BCE, with ancient poets like Hesiod, Aeschylus, and Virgil all writing of its frequent fireworks.