Most of us don't live near enough to volcanoes to think about them on a regular basis, but some scientists have spent a lot of time studying them and trying to understand their fickle ways. These days, we can often see the bad news coming, since most volcanoes send off a few warning shots before they erupt. That's a good thing, too, because when they blow go ... get out of the way!
No. 1 - Unzen, Japan
Mount Unzen's biggest eruption happened way back in 1792, when, along with a related tsunami, it killed 15,000 people. The Japanese volcano was largely quiet for the next 200 years or so. And then Unzen began to rumble. It started to ooze lava a couple weeks before it violently erupted in 1991, killing 43 people, including a group of scientists and reporters, and forcing the evacuation of thousands of homes. It remained active, releasing lava and ash until about 1995. Since then, it's been getting some much-needed rest.
