One of the most popular conspiracy theories in the Western world is that the 1969 moon landings were faked on a sound stage, possibly being directed by Stanley Kubrick, to give the United States an apparent victory in the Space Race against the Soviet Union.
A significant argument used by the conspiracists was the absence of photographs of the moon's surface showing the Apollo landing modules the astronauts used. This hit a hurdle when high-resolution NASA photographs were released showing the various space doohickies sitting there perfectly happy on the lunar landscape.
The insanity of attempting to fake such an immense event is the main argument against the conspiracy existing. Analyses have determined it would be more difficult to create and, crucially, maintain the fake than it would be to actually send someone up there.
In particular more than 400,000 people would have to be paid off or coerced to stay silent. But conspiracists are logic-proof, and so this conspiracy theory persists.