T his week is the anniversary of a landmark achievement in human history. On July 16, 1969, astronauts Edwin "Buzz" Aldrin, Neil Armstrong and Michael Collins left Earth in Apollo 11. A few days later on July 20, man took his first steps on the moon.

Frankly, we're still amazed at how they pulled it off. Both the astronauts in space and the NASA technicians on the ground had seemingly impossible obstacles to overcome, and they were forced to contend with unforeseen situations such as broken equipment, excess trash and unrelenting flatulence (seriously).

Check out these 10 strange-but-true facts related to the Apollo 11 mission:

1. Neil Armstrong’s famous quote was incorrectly transmitted. Instead of the saying, “That’s one small step for man,” the astronaut claims he said, "That’s one small step for a man." As he once clarified to a biographer: "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."

2. President Nixon was prepared for the worst, as was his speechwriter William Safire. Safire put together a tribute to the Apollo 11 astronauts just in case they never made it home. "In ancient days, men looked at stars and saw their heroes in the constellations," the president would have read in one of the speech’s poignant lines. "In modern times, we do much the same, but our heroes are epic men of flesh and blood."

3. The flag isn’t the only thing the Apollo 11 astronauts left behind. Over 100 items were discarded on the lunar surface, including a commemorative plaque and a gold replica of an olive branch, as well as trash items such as moon boots, a camera, urine containers, a portable life support system and air-sickness bags. (Armstrong and Aldrin were told to jettison their junk to make room for the samples they collected.) Several states have lobbied to make the lunar landing site a national monument in order to prohibit future moon travelers from stealing these items and selling them on eBay.

4. Neil Armstrong couldn’t afford the life insurance policy for an astronaut, so he, along with Buzz Aldrin and Michael Collins, hatched an alternate plan. Prior to their mission, the three signed hundreds of autographs while under quarantine. They then sent these autographs off to a friend, who would postmark them on the date of Apollo 11’s launch, and in the event of a tragedy, the friend would distribute the memorabilia to the astronauts’ families for them to sell for money.

5. The Apollo 11 mission insignia was designed by crew member Michael Collins. On astronaut Jim Lovell's advice, he chose an eagle (which he originally traced from a National Geographic book ) preparing to land on the surface of the moon with an olive branch in its beak. NASA, however, felt the eagle's talons looked too aggressive, so Collins resubmitted the design with the eagle holding the olive branch in its claws.

6. Upon entering the lunar module to begin their journey home, Buzz Aldrin and Neil Armstrong discovered that a switch on a crucial circuit breaker was broken, leaving them without a way to ignite the engine. They tried to sleep while NASA’s mission control worked out a solution, but Aldrin eventually decided to jam his felt-tip pen into the mechanism to use as a make-shift switch, and it worked.

7. According to Collins himself, the astronauts were plagued by "gross flatulence" as a result of excess bubbles in their beverages. "The drinking water is laced with hydrogen bubbles," he wrote in his 1974 autobiography "Carrying the Fire: An Astronaut's Journeys." "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."

8. The original footage from the lunar camera is gone. First noticed missing in 2006, the tapes were likely erased and reused to record data beaming back from one of several satellites launched in the 1980s. This lost footage, which was much clearer that what viewers saw on television, survives only in the broadcast formats.

9. Neil Armstrong was the first man on the moon for two reasons: firstly, because he was the senior astronaut of the two that descended to the lunar surface from the command module; and secondly, because the design of the lunar module forced him out before Aldrin. The placement of the hinges on the hatch made it so the door opened toward Aldrin, boxing him in. Armstrong, on the other hand, had a clear path. (Aldrin was apparently very upset by this.)

10. According to the astronauts who landed there, the moon has a smell. After tracking moon dust back into the lunar module and removing their helmets, astronauts Neil Armstrong and Buzz Aldrin thought the lunar materials smelled of "wet ashes in a fireplace" and "gunpowder," respectively. But back here on Earth, our oxygen-rich atmosphere renders the moon dust odor-free.