It was America's shining moment: after being beaten by the Russians in almost every aspect of the space race, the Americans made good on President Kennedy's promise to reach the moon. Astronauts Neil Armstrong and Buzz Aldrin became the first humans to step foot on another celestial body—the moon—on July 21, 1969 during the Apollo 11 mission. After saying his famous quote, "One small step for [a] man, one giant leap for mankind," Armstrong spent about two and a half hours on the surface. He and Aldrin returned to Earth by landing in the Pacific Ocean on July 24. 

Humans have never gone to another planet or celestial object other than the moon, and no other country has independently reached the moon in the decades following America's achievement. As Armstrong's quote suggests, this was, and will forever remain, one of America's humanity's greatest achievements.