Apollo conspiracy theory
Believers in the Apollo conspiracy theory allege that the Apollo moon landing missions never actually took place and that the lunar landings were filmed in a Hollywood studio. The "evidence" for this demonstrably false belief includes the allegation that the American flag placed on the Moon appears to wave in the windless lunar environment, the absence of stars stars appear in the lunar sky in photographs taken on the Moon (an effect of the speed of the film the astronauts used), and the allegation that shadows in the photographs run in different directions, rather than parallel, as if the sun were not the source of light. [1]
NASA denies this, pointing out that it can be conclusively demonstrated scientifically that the astronauts really went to the moon, for example, by analyzing the ages and composition of the rocks brought back by the astronauts. [2]