Main cause of the September 11 attacks on the US

The main cause of the September 11 attacks on the US was that the jihadi  terrorist group  Al Qaeda, did not like the growing US in the Islamic heartland of Saudi Arabia, especially when US allied with the Saudis on many occasions. This growing hatred led the Al Qaeda, led by Osama bin laden to destroy the twin towers. The main effects of this were that the US retaliated with force on Afghanistan. It tried to wed out the Islamic extremists in that area and was successful in killing Bin laden.