Here is a list of the world's greatest conspiracy theories. 1. September 11, 2001: The conspiracy theories surrounding the events of 9/11 ... continue to grow in strength. A large group of people - collectively called the 9/11 Truth Movement - cite evidence that an airliner did not hit the Pentagon and that the World Trade Centre could not have been brought down by airliner impacts and burning aviation fuel alone. Many witnesses - including firemen, policemen and people who were inside the towers at the time - claim to have heard explosions below the aircraft impacts (including in basement levels) and before both the collapses and the attacks themselves. As with the assassination of JFK, the official inquiry into the events - the 9/11 Commission Report - is widely derided by the conspiracy community and held up as further evidence that 9/11 was an inside job". 2. The assassination of John F Kennedy: Doubts about the official explanation ... surfaced soon after the [Warren Commission] report. Footage of the motorcade taken by Abraham Zapruder on 8mm film supported the growing belief that at least four shots were fired - not the three that the Warren Commission claimed. In 1979, the House Select Committee on Assassinations (HSCA) found both the original FBI investigation and the Warren Commission Report to be seriously flawed. The HSCA also concluded that there were at least four shots fired and that it was probable that a conspiracy existed.