Percentage of Americans: 7%
Who believes it: William L. Bryan, nuclear engineer and author; Clyde Lewis, radio talk show host

It's been nearly half a century since Neil Armstrong took "one small step for man, one giant leap for mankind." However, one of the longest enduring conspiracies is that Armstrong actually never took that step in the first place, or if he did, it was only somewhere on a film set in Hollywood Hills or Area 51. According to critics, the footage of the astronaut Aldrin placing the American flag on the soil proves that he was not on the moon. Why? The flag's waving, they claim, is impossible because of the moon's vacuumed atmosphere.