September 11, 2011 - Despite repeated claims by al-Qaeda that it planned the attacks on the World Trade Centre in New York, several official and unofficial investigations into the collapse of the Twin Towers suggest that structural failure was responsible.

Some theorists believe the U.S. government had prior warning of the attacks but did not do enough to stop them.

Others believe the Bush administration deliberately turned a blind eye to warnings to launch wards in the Middle East.

A large group of people who call themselves the 9/11 Truth Movement believe an aircraft did not hit the Pentagon and that the World Trade Centre could not have been brought down by an airliner impact and burning aviation fuel.

They say there is also video evidence to suggest there were puffs of smoke coming from the Twin Towers at levels far below the impact zones.

Many witnesses claim to have heard explosions before the aircraft impacts.



Some theorists believe the U.S. government had prior warning of the 9/11 attacks

The assassination of John F Kennedy -



The 35th President of the United States was shot on Friday, November 22, 1963, in Dallas, Texas at 12.30pm.



He was fatally wounded by gunshots while riding with his wife - Jacqueline Bouvier Kennedy - in a motorcade.



The ten-month investigation of the Warren Commission of 1963 to 1964, the United States House Select Committee on Assassinations (HSCA) of 1976 to 1979, and other government investigations concluded that the President had been assassinated by Lee Harvey Oswald - who was himself shot dead by Jack Ruby while in police custody.



However, there has always been doubts that Oswald was the lone gunman who fired shots from the Texas Book Depository which overlooked Dealey Plaza.



Footage taken by Abraham Zapruder on 8mm film supported the belief that at least four shots were fired and not three which the Warren Commission claimed.



There has always been doubts that Oswald was the lone gunman who fired shots from the Texas Book Depository

It has also been suggested that at least one of the shots came from a completely different direction. Many believe shots were fired by a gunman hiding behind a picket fence on a grassy knoll overlooking the plaza.



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.



However, later studies, including one by the National Academy of Sciences, have called into question the accuracy of the evidence used by the HSCA to support its finding of four shots.



A flying saucer crashed at Roswell in 1947 - What is certain is that something did crash at Roswell, New Mexico, sometime before July 7, 1947 and - at first - the U.S. authorities stated explicitly that this was a flying saucer or disk.



Numerous witnesses reported seeing metallic debris scattered over a wide area and at least one reported seeing a blazing craft crossing the sky shortly before it crashed.



In 1989, former mortician Glenn Dennis claimed that he was involved in alien autopsies which were carried out at the Roswell air force base.



Some theorists believe autopsies were allegedly carried out on aliens who crashed in the New Mexico desert which was then covered up by American authorities

Weight has been added to the conspiracy theory due to the U.S. military repeatedly changing its story.

Since the late 1990s, several former pro-UFO researchers have concluded that the craft was, indeed, part of a U.S. military project and that it was, most likely, some sort of weather balloon.



However, Walter Haut, the Roswell Army Air Field public affairs officer, said he saw alien corpses and a craft which was involved in a military cover up. He died in 2005.



Nasa faked the moon landings -



Some theorists believe Apollo astronauts did not land on the Moon.



They claim Nasa and possibly others deceived the public into believing the landings.



They have pointed to photographs from the lunar surface which they claim show camera crosshairs partially behind rocks, a flag planted by Buzz Aldrin moving in a strange way, the lack of stars over the lunar landscape and shadows falling in different directions.



Fake? Astronaut Buzz Aldrin, lunar module pilot, walks on the surface of the Moon in July 1969

The Jesus conspiracy - The theory that launched the novel The Da Vinci Code and a film of the same name.



Theorists believe Jesus married Mary Magdalene, had one or more children, and that those children or their descendants emigrated to southern France.



Once there, they intermarried with the noble families that would eventually become the Merovingian dynasty, whose special claim to the throne of France is championed today by a secret society called the Priory of Sion.



Theorists believe Jesus married Mary Magdalene, had one or more children, and that those children or their descendants emigrated to southern France

Elvis Presley faked his own death - There has been a belief that Elvis did not actually die in 1977. Many even think he is still alive and that he went into hiding.



Two tabloid newspapers ran articles covering the continuing 'life' of Presley after his death including a broken leg from a motorcycle accident, all the way up to his 'real death' in the mid 1990s.



There has been a belief that Elvis did not actually die in 1977. Many even think he went into hiding

Operation Northwoods - A conspiracy involving a plan by the Joint Chiefs of Staff to launch a fake Cuban terror campaign on American soil to persuade the U.S. public to support an invasion against Castro.

The plan involved bombings and the simultaneous hijacking and blowing up of American airliners.

The operation was quashed by President Kennedy leading many to speculate that it was linked to his assassination a year later.

The plan has also been linked by theorists who believe that the September 11, 2001 attacks were a so-called 'inside job' because of the use of airliners.

North American Union - The North American Union (NAU) is a theoretical regional union of Canada, Mexico and the United States similar in structure to the European Union, sometimes including a common currency called the amero.



Theorists who believe that the three countries are planning for this believe that it is part of a global conspiracy to set up something called the New World Order (NWO). Officials from all three nations have repeatedly denied that there are plans to create a NAU.

Pearl Harbor was allowed to happen - Theorists believe that President Franklin Roosevelt provoked the Japanese attack on the U.S. naval base in Hawaii in December 1941, knew about it in advance and covered up his failure to warn his fleet commanders.



Sailors at Naval Air Station Ford Island watch as the destroyer USS Shaw explodes after an attack by Japanese carrier based strike aircraft on the Hawaiian port of Pearl Harbor December 7, 1941

He apparently needed the attack to provoke Hitler into declaring war on the U.S. because the American public and Congress were overwhelmingly against entering the war in Europe.



Theorists believe that the U.S. was warned by the governments of Britain, the Netherlands, Australia, Peru, Korea and the Soviet Union that a surprise attack on Pearl Harbor was coming and that the Americans had intercepted and broken all the important Japanese codes in the run up to the attack.





