10 Conspiracy Theories People Actually Believe
2. There's A Military Base On The Moon
The fact that almost half of the moon has never been seen from Earth means there's a whole lot of moon to be populated by the persecution complexes of illogical people. Thus there's either an American facility, an alien colony, or a Nazi moon base there depending on who you ask.
The plentiful photographs of the dark side of the moon need to be fakes for this theory to work, and so everyone from NASA is presumed to be a part of the cover-up.
One piece of evidence for the Nazis having somehow got to the moon is documentation about a Nazi space project run by German commander Hans Kammler. This was a delicious piece of trivia for the theory's fans to trot out, so it's unfortunate for them that it turned out to be a piece of marketing for the movie Iron Sky.
In the more extreme versions of this theory, the moon is completely hollow, and is actually a Death Star-like space station. It's usually run by aliens, including the reptilian blood-drinking shapeshifters described by prolific conspiracy author David Icke.