5. The mysterious death of Marilyn Monroe is still very intriguing mostly because of the numerous conspiracy theories around it. The Hollywoods legend was found dead in 1962, naked in her bed, with a phone in her hand. According the official story, Marilyn died of drug overdose and she probably committed suicide. However, many people believe she was actually murdered; there are many conspiracy theories that claim she was murdered because of President Kennedy or the fact that she knew a lot of secrets so she had to be eliminated.