Apollo 11 Passive Seismic Experiment Package (PSEP), 1969.

UNITED STATES - DECEMBER 22: A full size model of one of the lunar surface experiments carried out by Neil Armstrong and Edwin �Buzz� Aldrin during the first manned lunar landing mission, on 20th July 1969. When Armstrong and Aldrin climbed down the steps of the Apollo 11 Lunar Module to become the first humans to set foot on another planetary body. �One small step for man, one giant leap for mankind�, were Armstrong�s famous words as he reached the surface. The astronauts carried out a variety of experiments before lifting off from the Moon�s surface 21 hours and 36 minutes after landing, rejoining Michael Collins in the Command Module in lunar orbit. The three astronauts then successfully returned to Earth, and a heroes� welcome. (Photo by SSPL/Getty Images)