Overturned cars. Destroyed houses. Snapped power lines. The powerful winds of a tornado can cause a devastating amount of damage in a short time. Get an up-close look at how tornadoes form and learn about some of history’s worst twisters.

A path of devastation -- Tornado basics -- Tornado alleys -- Sizing up a tornado -- The world's worst tornadoes -- Storm chasers and spotters -- Staying safe.