2. Mount Vesuvius, Italy
Mount Vesuvius is located less than six miles from Naples…and it’s considered one of the world’s most dangerous volcanoes out there. The last time it blew was in 1944, but its most famous eruption was in 79 AD when it obliterated Pompei and Herculaneum. With over 3 million people living nearby and tourists flocking to stroll around the summit, this could be the site of another tragic disaster one day.