A tornado is an atmospheric vortex that occurs in rain or thunderclouds. It looks like a cloudy funnel, which often descends to the ground level and spreads at high speed, causing significant damage. Although tornadoes can, and do, happen everywhere, the US gets hit the hardest, with an average of around 1,150 tornadoes annually.
So, from the American Midwest to the plains of Bangladesh, click on for some of the most terrifying tornadoes in history.