Climbers have for decades wondered whether British national George Mallory did reach the summit of Mount Everest with his partner Sandy Irvine in 1929, almost 25 years before Edmund Hillary and Sherpa Tenzing.
Now, it seems that the Mount Everest's biggest mystery has been solved, after US climber Conrad Anker, who discovered Mallory's body on Mount Everest in 1999, re-traced the doomed explorer's footsteps on the mountain.
With British partner Leo Houlding, 47-year-old Anker used 1920s clothing and equipment to see if, in theory at least, Mallory and Irvine could have beaten Hillary.
A documentary film, The Wildest Dream: Conquest Of Everest, shows they succeeded.
"It was harder than I expected, but it's possible Mallory and Irvine could have done it," the 'Sunday Express' quoted Anker as saying.
Mallory and Irvine died on the mountain after being seen 800ft from the summit.
In re-tracing Mallory's footsteps Anker was honouring the man he had idolised since childhood and whose immaculately preserved body he had found on the mountain as part of the Mallory and Irvine Research Expedition.
It was a discovery, he confesses, that haunted him for some time. "Had I broken some taboo? Had I overstepped something? It was pretty heavy stuff. It weighed on me," he was quoted as saying.