" Ahead of them stretched one of the most remarkable mountain vistas on earth. The Rongbuk Valley spreading south toward Everest rises in twenty miles but 4,000 feet, and it runs remarkably straight. From even a slight elevation, it appears to be flat, with its massive ice fields seeming to lie prostrate along the valley floor, as if detached from the mountain from which they flow. High ridges on both flanks draw the eye irresistibly to the head of the valley, where the sheer scale of the North Face, towering 10,000 feet, collapses perspective, creating an illusion of both proximity and depth, as if the mountain could be reached in a moment, or never reached at all. "

― Wade Davis , Into the Silence: The Great War, Mallory and the Conquest of Everest