British born George Mallory, the person tasked with heading the team who first set out to climb Mount Everest in 1921, overlooked what is now used as the doorway to Mount Everest, the entry point of East Rongbuk Glacier. When Mallory first viewed this entry point, a narrow cliff within the mountainside wall, he dismissed it as too modest and small to warrant further investigation. Canadian Oliver Wheeler however was educated in the science of topography and geography from his father who surveyed the Canadian west coast Rocky Mountains and because of this, he did not view the dimensions of the cut to be as important as the pulse of water pouring out of that cut every afternoon. This enormous volume of expelled water signaled to Wheeler that a glacier had to be present at the head of the valley as it was the only possible explanation which fit. On July 30, 1921, Wheeler set out for the East Rongbuk Glacier and as he anticipated, he was able to make it up the ice field within 6 short days. As the East Rongbuk Glacier widened and curved around, it came directly to the base of the North Col, a sharp edged pass carved by glaciers in the ridge connecting Mount Everest and Changtse (pronounced “chang-see”). This opening became the key to unlocking Mount Everest and is still leveraged by climbers into the modern day. 6 days after setting out, on August 4, 1921, Wheeler sent a dak runner, which is essentially a Tibetan messenger, with a sketched map indicating his discovered exploit of the armor of Mount Everest for Mallory