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[1] including that there was
advance knowledge of the attacks among high-level government officials. Government investigations and independent reviews have rejected these theories.
[2][3] Proponents of these theories assert that there are inconsistencies in the commonly accepted version, or evidence that was either ignored or overlooked.
[4]