July 21 marks the 45th anniversary of Neil Armstrong and Edwin "Buzz" Aldrin walking on the Moon (the duo landed hours earlier on July 20, 1969).

Here are some facts you may not have known about the Apollo 11 mission:

1. Armstrong's famous quote was incorrectly transmitted. He claims he intended to say, "That's one small step for a man..." The astronaut told a biographer, "I think that reasonable people will realize that...the 'a' was intended because that's the only way the statement makes any sense."

2. The Apollo 11 astronauts left behind more than just the American flag. Over 100 items were left on the Moon, including a commemorative plaque, golden olive branch, and trash like moon boots, a camera, urine containers, and air-sickness bags. The trash was left to make room for rock and soil samples they collected.

3. The astronauts had to deal with "gross flatulence." "The drinking water is laced with hydrogen bubbles," wrote Apollo 11 astronaut Michael Collins. "These bubbles produced gross flatulence in the lower bowel, resulting in a not-so-subtle and pervasive aroma which reminds me of a mixture of wet dog and marsh gas."

4. The original footage of the lunar camera is gone. The missing original was first noticed in 2006, and the tapes were likely later erased and reused to record other data. The original video was much clearer than what was seen on TV.

5. The Moon has a smell. After tracking Moon dust back into the lunar module and removing their helmets, Armstrong and Aldrin thought it smelled like "wet ashes in a fireplace" and "gunpowder," respectively. Because of the Earth's atmosphere, the smell is now unnoticeable. 

Read more: Fox News

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