On July 20, 1969, NASA's Apollo 11--crewed by Neil Armstrong, Michael Collins and Edwin "Buzz" Aldrin--successfully carried out the first lunar landing.
The video above, courtesy CNN, offers a montage of the sights and sounds from the historic mission, including the famous pronouncement Neil Armstrong made upon touching down.
However, that famous line was reportedly uttered with an error. Numerous sources, including the LA Times, report Armstrong intended to say, "That's one small step for a man, one giant leap for mankind" but accidentally omitted the "a".
The LA Times reports Armstrong told biographer James Hansen: "I think that reasonable people will realize that I didn't intentionally make an inane statement and that certainly the 'a' was intended, because that's the only way the statement makes any sense."
And that's not the only bit of Apollo 11 history that wasn't common knowledge until many years later. Officials actually prepared a speech for President Richard Nixon to give "In the event of moon disaster." The sad but inspiring speech was released several years ago. You can read the speech below, which is courtesy the National Archives.