Abbey Gate +5
The events of 9/11/01 were the largest attack against the US since the Japanese struck Pearl Harbor in 1941, and the most destructive single act of terrorism in history. The responsibility for masterminding, planning, organizing, and executing the operation lay with members of Al Qaeda (the Base). The extremist Islamic group had spent years organizing, coordinating, and conducting terrorist attacks on western interests, particularly the US, since the end of the Gulf War in 1991.