Originally Posted by InfoGuy

Montana and Wyoming are the home of Yellowstone National Park. What lies beneath is an active supervolcano, the largest volcanic system in North America. While the chances of a mega eruption are slim, it's a huge ticking bomb that could could go off at any time. The last mega eruption 640,000 years ago is estimated to have been about 1.5 million times more powerful than the Little Boy atomic bomb dropped on Hiroshima.