This event repeats every year forever
There are many conspiracy theories that attribute the planning and execution of the September 11 attacks against the United States to parties other than, or in addition to, al-Qaeda, including that there was advance knowledge of the attacks among high-level government officials. Government investigations and independent reviews have rejected these theories. Proponents of these theories assert that there are inconsistencies in the commonly accepted version, or evidence that was either ignored or overlooked.
The most prominent conspiracy theory is that the collapse of the Twin Towers and 7 World Trade Center were the result of controlled demolitions rather than structural failure due to impact and fire. Another prominent belief is that the Pentagon was hit by a missile launched by elements from inside the U.S. government or that a commercial airliner was allowed to do so via an effective stand-down of the American military. Possible motives claimed by conspiracy theorists for such actions include justifying the invasions of Afghanistan and Iraq (even though the U.S. government concluded Iraq was not involved in the attacks) to advance their geostrategic interests, such as plans to construct a natural gas pipeline through Afghanistan. Other conspiracy theories revolve around authorities having advance knowledge of the attacks and deliberately ignoring or assisting the attackers.
Our hearts go out to the victims of this terrible event, regardless of who or what perpetrated it.