Magma Bubbles from Mt Etna . ... Etna erupted spectacularly in 2001 June. Pictured above , the volcano was photographed expelling bubbles of hot magma, some of which measured over one meter across. ... Etna is because of its likely similarity to volcanoes on Mars . ... Etna is not only one of the most active volcanoes on Earth , it is one of the largest , measuring over 50 kilometers at its base and rising nearly 3 kilometers high. ... NASA Web Site Statements, Warnings, and Disclaimers . ...