My favourite pre-dates social media by decades, originating in the 60s: the theory that Paul McCartney was killed in a road accident in about 1964, and replaced by a look-alike. Its proponents claim that there are all sorts of clues in the band's later songs and albums. The twist is that they are probably right about the clues: The Beatles were well aware of the theory, and may have mischievously added them.
As for the link's claim that the cameras survived the nuclear explosions they were filming, it is noticeable that all the films suddenly cut out just as the debris cloud gets to them, so no doubt the camera was destroyed, but transmitted its film to a distant recording facility first.
