Buzz Aldrin's bootprint, Apollo 11

Apollo 11, July 20, 1969. Often mistaken for Neil Armstrong's first step, this is Buzz Aldrin's boot, and he took the picture himself. It was a science photo before it was an icon: Aldrin shot the print to show how the fine lunar soil packed under weight, which mattered to everyone planning later walks and rover drives. The sharp tread edges show how cohesive the powdery surface is.