Last Updated: Wednesday, May 22, 2013, 08:43
Wind, humidity and rainfall combined precisely to create the massive killer tornado in Oklahoma.
Last Updated: Sunday, February 17, 2013, 13:26
The meteor that streaked across the Russian skies on Friday, injuring around 1,200 people, exploded with a force 30 times greater than the Hiroshima nuclear bomb, NASA scientists say.
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