The idea for the attacks came from Khalid Sheikh Mohammed , who first presented it to Osama bin Laden in 1996 . At that time , bin Laden and al-Qaeda were in a period of transition , having just relocated back to Afghanistan from Sudan . The 1998 African Embassy bombings and bin Laden 's February 1998 fatwā marked a turning point of al-Qaeda 's terrorist operation , as bin Laden became intent on attacking the United States
1998 African Embassy bombings
1998 United States embassy bombings
September 11 attacks