The perpetual layers of ice and snow on Mount Rainier that could contribute to lahars would fill the Seattle Mariners' stadium, Safeco Field, 1,700 times.
Sri Lanka, with a population of more than 19 million, has the highest per capita death rate from snake bites, averaging 800 a year.
When multiple tornadoes devastated the suburbs of Oklahoma City on May 1999, scientists measured wind speeds of 301 miles per hour in an F5 tornado, the highest ever recorded in a tornado.
The first helmet standards grew out of research from the 1950s, when scientists at Michigan's Wayne State University dropped cadavers down an elevator built to study G-force impacts on the human head.
Narrator: Beware, you may have just seconds to live. Some of the world's most dangerous encounters are closer than you think. Danger lurks in a long slumbering volcano near a major American city, and in a massive funnel cloud at your doorstep. It has highly toxic fangs and can even paralyze you with one nasty helmet to helmet hit. And don't forget to pull your chute. Now, Most Dangerous, on Modern Marvels.