British explorer Sandy Irvine's foot discovered 100 years after he vanished on Everest

Remains believed to belong to a British explorer who vanished more than 100 years ago while climbing Mount Everest have finally been found.

Andrew Comyn "Sandy" Irvine, aged 22, disappeared along with the mountaineer George Mallory in June 1924. The pair were attempting to become the first people to scale the world's highest peak.

It's still a mystery whether they succeeded in their goal before they died. Mallory's remains were discovered in 1999, which were missing a photograph of his wife that the climber had planned to leave on the summit. Irving, who had been carrying a Kodak camera that may have recorded a possible historic summit, was never recovered. The summit was officially first reached 29 years later, when Edmund Hillary and Tenzing Norgay scaled Everest from its south side in 1953.

Now, a National Geographic documentary team, including the Oscar-winning director Jimmy Chin and the climbers and filmmakers Erich Roepke and Mark Fisher, have found what they believe is Irvine's foot.

Encased in a boot and wearing a sock stitched with his name, the foot was discovered on Everest's Central Rongbuk Glacier, further down the mountain from Mallory's remains.

"I lifted up the sock," Chin told National Geographic, "and there's a red label that has A.C. IRVINE stitched into it."

Irvine and Mallory were last seen on June 8, 1924, as they set off to scale the summit. One of their expedition teammates, Noel Odell, reported spotting the two near the second of the mountain's three steps as two tiny black dots. One of the dots broke past the skyline during a brief parting of the clouds, then they disappeared.

Mallory's body was found less than 2,000 feet (600 meters) from the summit by the U.S. rock climber Conrad Anker. Mallory's remains were tied by a rope around the waist and had injuries suggesting that the pair had fallen while connected together.

By searching near these remains and scouring the glacier for clues, Chin and his team located the boot melting out of the ice.

"This was a monumental and emotional moment for us and our entire team on the ground, and we just hope this can finally bring peace of mind to his relatives and the climbing world at large," Chin said.

The team sent the remains to China Tibet Mountaineering Association, which is responsible for climbing permits on Everest's northern side. The find was also reported to the Royal Geographical Society, which organized Irvine and Mallory's expedition, and Irvine's great niece and biographer, Julie Summers.

"I have lived with this story since I was a 7-year-old when my father told us about the mystery of Uncle Sandy on Everest," Summers said, as reported by the Guardian. "When Jimmy told me that he saw the name AC Irvine on the label on the sock inside the boot, I found myself moved to tears. It was and will remain an extraordinary and poignant moment."

The Irvine family has volunteered to take a DNA test so that the identity of the remains can be conclusively determined. Meanwhile, Chin and his team will continue to search for more artifacts. If Irvine's camera is found and it can prove they scaled the peak, it could potentially rewrite history.