Climbers' shadows trace a line up a snow ridge during acclimatization climbs in the Khumbu Valley. This is preparation for entering the death zone above 26,000 feet, where human bodies begin dying cell by cell. The diagonal divide between foreground slope and background peaks creates visual tension; the shadows add human scale to vast terrain. Shadow Line references both the visual element and the mountaineering metaphor; crossing the line into extreme altitude where survival is measured in hours. This is the threshold before the ultimate unknown.