Rare volcanic vortex rings were spotted rising above Mount Etna in Italy recently. The natural phenomenon occurs when gases ...

Historic volcano puffs out stunning 'vortex rings' above crater: See the best photos of Italy's Mt. Etna and its rings.

The Backyard Scientist tests the world's largest cannon that shoots rings of air.

Europe's largest volcano began blowing spectacular ‘smoke rings’ into the sky last week. View on euronews ...