It's one of the most famous quotes in history. It's one you probably can also recite by heart. Yet, for more than 50 years, it's a quote that we have all gotten wrong!

I'm talking about Neil Armstrong's first words when he set foot on the moon. 

Speaking to the press in the days after the Apollo 11 spacecraft landed on the moon, the astronaut who took the historic first step admitted that people watching on TV and listening on the radio misheard him.

"That's one small step for man, one giant leap for mankind," Armstrong proudly announced…or so everyone assumed.

So, what did Armstrong really say? And does it change the meaning of a line that's been printed in history books for decades?

After collecting rock samples and staking the American Flag into the lunar surface, the astronauts returned to Earth, splashing down in the Pacific Ocean at 12:51 p.m. on July 24. Upon completing a 21-day quarantine, Armstrong spoke to the press and explained that his message was incorrectly transcribed.

He thought he'd said, "That's one small step for a man, one giant leap for mankind," which intensifies the contrast between the two halves of the phrase. Without the "a," the phrase essentially means, "That's one small step for humanity, one giant leap for humanity."

Adding the "a" makes Armstrong's intended meaning easier to interpret: the moon landing was a physically small act for him as an individual, but a colossal achievement for humanity and the advancement of space exploration.

Armstrong listened to the recording years later and admitted that he couldn't hear himself say "a" either. In 2006, computer programmer and speech analyst Peter Shann Ford used modern equipment to analyze the recording and concluded that the astronaut did, in fact, say "a," but it was muffled by static.

Regardless of what was said or what was heard, the action speaks for itself. Armstrong really did take a small step onto the moon in 1969, and it really was, then and now, a giant leap for humanity.