Contains photographs from Y-Day dating from approximately 1906 to the 1970s. Photographs are of students whitewashing the Y on the mountain, including preparing the supplies, the ascent up the mountain, and the assembly line to pass up the whitewashing lime. Also contains aerial photographs of the Y in addition to photographs from the 1958 preparation and burial of a time capsule. Also includes winning photographs from a Y-Day-related photo contest.