There are several theories regarding the attacks that were made on September 11th, 2001 in the US. There are several individuals and groups who advocate several theories on 9/11. This was a result of the truth movement that was started to get to the bottom of what actually happened and what was the real cause of these attacks. Many forums on the internet became rife with rumors from the time the attacks took place, some theories surfacing about six hours from the time the attack took place. The first theory that was put forward was that the fall of the twin towers was a controlled demolition plan that was made to look like an accident by the two planes hitting the two towers. This theory became popular among conspiracy theorists as it was felt that, with the highly vigilant intelligence communities who work in tandem with the higher authorities, how was it possible that such attacks were not preempted and averted.
The other theories were several as well, besides the involvement of the terrorist group al Qaeda that was well established. Many wanted to look below or further and discover the real reason why such attacks were called into operation. There were theories how the strikes were a result of the attacks made by the US in Iraq and Afghanistan. Though the real story and truth never emerged, the fact that millions of lives were lost or impacted by these attacks remains a truth that needs to be avenged and hopefully, it will, sometime in the future.