5. Mount Etna, Italy
Mount Etna, Europe’s most active volcano, looms over Sicily and frequently erupts with lava flows, ash clouds, and seismic activity. Its eruptions can disrupt flights and cover nearby towns with ash. Despite its frequent activity, a major eruption could cause significant destruction. Etna’s unpredictable behavior keeps scientists on alert, as each eruption reminds the world that this towering volcano remains a powerful and active threat.