Image Credit: AP

1 ‘THEY KNEW IN ADVANCE': Immediately after the attacks, President George W. Bush said that nobody in the US government "and I don't think the prior government, could envisage flying air planes into buildings." Just weeks before, however, when Bush and other world leaders met for the annual G8 summit in Genoa, Italy, security planners had prepared for that exact scenario. Anti-aircraft missiles were deployed near the Genoa site because the Italians had a threat that a plane would be used as a missile to kill the G8 leaders. And Norad planners had prepared for such a scenario themselves in training exercises.

2 THE CONTROLLED EXPLOSION: Conspiracy theorists including physicists and software engineers believe the twin towers of the World Trade Centre were brought down in controlled explosions, not as a result of being struck by separate planes. The thinking comes from the fact that the two towers imploded neatly to the ground, rather than toppling over as expected. The theorists believe that large amounts of explosive were hidden in the towers, and strategic supporting beams of the building were pre-cut, allowing the towers to fall on their foundations. And because of security at the site after the collapse, the requisite evidence was removed and sent for recycling.

3 INSIDER TRADERS PLANNED IT: Before 9/11, there was a series of unusual stock trades on companies which would feel the negative and positive effects of the attacks. United Airlines and American Airlines, both of whom lost planes in the attacks, were sold heavily prior to 9/11. None of the other US carriers saw such activity on their stocks. And defence corporations, who would benefit from an aggressive military backlash, were also strong buys in the week before the attack. Morgan Stanley, based at the World Trade Centre, was a strong sell. Insurers were also heavy sells. The US Security and Exchange Commission even launched an investigation into Wall Street's activity around the attack.

4 STAND THE PLANES DOWN: Norad, the North American Defence Command, had advance knowledge of the hijacked planes and ordered their fighters to "stand down" or deliberately scramble them late so as they could not prevent the planes from reaching their intended targets. Surely Norad, responsible for air defences, has the capability to locate big, lumbering passenger planes. Haven't they got the latest radar? So why weren't they scrambled in time to prevent the tragedy? And why were two scrambled jets ordered out into military airspace over Long Island when New York City was under attack?

5 THE PENTAGON ‘PLANE': Conspiracy theorists argue that the Pentagon was not hit by American Airlines Flight 77. The most secure defence building in the world has banks of surveillance cameras scanning its perimeter. But none of the cameras picked up a clear image of the plane. Instead, it must have been a missile launched by rogue elements with the US government itself. And the hole made by the plane was barely 20 metres across — but the wingspan of a Boeing 757 is 40 metres from tip to tip. The hole punched in the Pentagon is too neat to come from a speeding plane and the building itself sustained little comparative damage if it really was a plane. It had to be a missile.

6 THE BLACK BOXES: All of the airplanes used carried two black boxes each. The official report on 9/11 says that none of the four black boxes from the two planes that hit the twin towers was recovered from the debris. But two men who worked on the debris field say that they helped federal agents recover three of the four there. And the Pentagon black boxes were conveniently too damaged to recover information from. Only on United 93, where passengers and crew fought back, forcing the plane into a corn field in rural Pennsylvania, were the boxes recovered. Even then, it took seven months before the families could listen to tapes, and a full five- and- a-half years before they were produced at the trial of so-called 20th hijacker.

7 BLAME CIA AND MOSSAD: A former President of Italy gives conspiracy theories fuel when he assets that all of the Italian centre-left knows that the Central Intelligence and Mossad were behind the attacks, making Muslim terrorists as the fall guys. This allows the US to throw its full weight behind Israel. In addition, a former head of Pakistan's Inter-Service Intelligence agency asserts that the ISI had prior knowledge of the attacks, knowing that the CIA was acting with Israeli operatives to plan and mount the attacks. And the attacks were a perfect opportunity for the forces of Zionism to take control of world affairs in retribution.

8 THE ‘NO-PLANERS': Given that the Boeing planes supposedly used in the attacks are made largely of aluminium, it is physically impossible for the planes to cause as much damage as they did to the World Trade Centre and the Pentagon. They were actually missiles with hologram effects, according to conspiracy theorist videos circulating on the internet. The theories are supported by their frame-by-frame analysis of the strikes at the twin towers. Fractional advancing of the tapes clearly show a cigar-shaped object, not a plane. Besides, the heat cause by airplane fuel could not possibly get hot enough to melt the steel beams supporting the towers.

9 OIL'S WELL THAT ENDS WELL: The price of oil prior to 9/11 had been steadily declining due to increased production capacity and new finds. But having a dramatic attack on the US blamed on Muslim terrorists would have an immediate and long-term effect on oil prices. With the Middle East thrown into turmoil, military action would be justified to protect strategic oil interests, conspiracy theorists argue. Besides, who other than ‘Big Oil' could afford to plan and mount such an operation.

10 RIDING THE WRECKAGE: Conspiracy theorists add credence to an urban legend that a firefighter survived the collapse of the North Tower by riding on a piece of debris as it fell along a steel beam, surviving the fall from the 82nd floor. Another version is that an employee at a financial company — an avid surfer — rode the waves of dust and debris down safely as the building collapsed. Sadly, these two stories are not true. But the rest ...?