By Issy Ronald for CNN
Andrew Irvine (back row, far left) and George Mallory (back row, second from left) were members of the 1924 British Mount Everest expedition. Photo: Supplied / Royal Geographic Society
When a National Geographic documentary team discovered a boot and sock sticking out of a melting glacier on Mount Everest in September, they almost immediately recognised its significance as a clue to a century-old mystery.
A name label still stitched onto the woollen sock read "A.C. Irvine," revealing that it probably belonged to British climber Andrew "Sandy" Irvine. Irvine's disappearance on Everest in 1924, alongside his compatriot George Mallory, is one of mountaineering's biggest mysteries - with a solution that has the potential to change history.
The pair disappeared on 8 June 1924, 800 feet below Everest's summit, as they set off to complete the first documented ascent of the world's tallest mountain. But whether they made it to the summit, thus becoming the first known people to reach this milestone, before they died is still unknown.
While Mallory's body was discovered in 1999, neither Irvine's body nor the camera that the climbers were carrying - which might reveal whether they reached the summit - have ever been found.
That is, until this latest expedition, when the National Geographic team, which included Free Solo co-director Jimmy Chin, discovered a foot inside what they believe is Irvine's boot. While they are waiting for DNA confirmation, comparing samples from the foot with ones taken from members of Irvine's family, it appears to be the first evidence of his death since his disappearance.
"It's the first real evidence of where Sandy ended up," Chin said, according to National Geographic. "A lot of theories have been put out there.
"When someone disappears and there's no evidence of what happened to them, it can be really challenging for families. And just having some definitive information of where Sandy might've ended up is certainly (helpful), and also a big clue for the climbing community as to what happened."
Photo: Screenshot / Instagram / National Geographic
A few days before they found the boot, the team discovered an oxygen cylinder from a 1933 expedition that had also attempted to scale Mount Everest. Though that expedition failed, it had found an ice axe belonging to Irvine on the mountain's northeast ridge, leading Chin's team to speculate that they might be close to his body.
Following that hypothesis, they spent the next few days scouring the glacier, until filmmaker and climber Erich Roepke spotted the boot.
"I think it literally melted out a week before we found it," said Chin.
Chin and the team took the boot and foot off the mountain in a cooler when they noticed birds disturbing it and gave it to the China-Tibet Mountaineering Association (CTMA).
Shortly after their discovery, the team informed Irvine's family, including his great-niece Julie Summers, who has written a book about the climber.
Summers was "moved to tears" when she learnt of the boot's existence in an "extraordinary and poignant moment," she said, according to the PA Media news agency.
"I have lived with this story since I was a seven-year-old when my father told us about the mystery of Uncle Sandy on Everest," she added.
"The story became more real when climbers found the body of George Mallory in 1999, and I wondered if Sandy's body would be discovered next. A quarter-of-a-century after that discovery, it seemed extremely unlikely that anything new would be found."
- CNN