The September 11 attacks were the deadliest terrorist attacks in human history, causing the deaths of 2,996 people, including 2,977 victims and 19 hijackers who committed murder–suicide.

The aircraft hijackers in the September 11 attacks were 19 men affiliated with jihadist organization al-Qaeda.

At around 9:30pm on September 11, 2001, George Tenet, director of the Central Intelligence Agency, told President George W. Bush and U.S. senior officials that the CIA's Counterterrorism Center had determined that Osama bin Laden and al-Qaeda were responsible for the September 11 attacks.