From the assassination of John F Kennedy to the death of Diana, Princess of Wales. From Roswell, New Mexico, to Nasa's moon landings. From the bloodline of Christ to the death of Elvis Presley. From the Moscow appartment bombings to the Indian Ocean tsunami. From Pearl Harbour to Peak Oil, the Philadelphia experiment and Pan Am flight 103. Every major event of the last 2,000 years has prompted a conspiracy theory and here we examine those with the biggest followings and the most longevity. 1. September 11, 2001. Thanks to the power of the web and live broadcasts on television, the ... theories surrounding the events of 9/11 ... have surpassed those of Roswell and JFK in traction. The [alternative] theories continue to grow in strength. At the milder end of the spectrum are the theorists who believe that the US government had prior warning of the attacks but did not do enough to stop them. Others believe that the Bush administration deliberately turned a blind eye to those warnings because it wanted a pretext to launch wars in the Middle East to usher in another century of American hegemony. 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.