9/11 is shorthand for four coordinated terrorist attacks carried out by al-Qaeda, an Islamist extremist group, that occurred on the morning of September 11, 2001.
Who is responsible for 9 11?
The FBI and its partners quickly learned that the 9/11 attacks were carried out by bin Laden's terrorist organization. The 19 men who hijacked and crashed the four planes were all trained by al Qaeda, and bin Laden eventually admitted to his role in orchestrating the attacks.