13 November

Andrew Irvine (L) and George Mallory. Possibly the first to reach the top of Mt Everest in the 1920s. Nobody knows, Mallory's body was found by American climbers a few years ago, nearly a century later, mummified by the cold, face down in the rocks. (See second pic.) Irvine has never been found, and had the camera that could have proved if they reached the summit. Conspiracy theorists say Chinese climbers took Irvine's body and camera to disguise that he and Mallory got to the top of Everest using the north face first (the Chinese were the first to do this officially, mid-20th century). The more likely explanation is that Irvine fell thousands of metres and his body has been covered by a century of snow and avalanches. Injuries to Mallory's body suggest he fell, and Irvine held him by a rope, which he was then forced to cut.