We went into Afghanistan because 911 was conceived, planned and controlled from there
I think it was "conceived" in the Philippines. Some planning was also done in Malaysia.
According to the intelligence authorities in the United States and the Philippines, the September 11 attacks originated with Operation Bojinka (a plan that was not executed), which was conceived by Khalid Sheikh Mohammed (K.S.M) and his nephew, Ramzi Yousef.
Several Al-Qaeda members are said to have attended a meeting in Kuala Lumpur, Malaysia, from January 5 to January 8, 2000, that regarded the planning of the USS Cole bombing (which took place on October 12, 2000), and the forthcoming September 11, 2001 attacks. Hambali, Ramzi bin al-Shibh, Nawaf al-Hazmi, Khalid al-Mihdhar, and Tawfiq bin Attash attended the meeting. The men were also photographed when they came out of the meeting.