In 1924, British mountaineers George Mallory and Andrew Irvine set out to climb to the top of Mount Everest, nearly 30 years before Sir Edmund Hillary and Tenzing Norgay's successful ascent in 1953. Mark Synnott, author of The Third Pole, posits that photographic evidence of Mallory and Irvine's summit of Mount Everest may still exist from Irvine’s Vest Pocket Kodak camera.

I've long wondered whether Mallory and Irvine managed to make it to the peak—without supplemental oxygen, no less. Regardless of whether or not evidence ever surfaces that they did, Hillary and Norgay will forever remain the first to do it and live to tell the tale.