Who was the perpetrator in September 11?

The perpetrators of the September 11, 2001 attacks were 19 terrorists affiliated with the extremist group al-Qaeda, led by Osama bin Laden. They hijacked four commercial airplanes, crashing two into the World Trade Center towers in New York City, one into the Pentagon in Arlington, Virginia, and the fourth, United Airlines Flight 93, was intended for another target but crashed in Pennsylvania after passengers intervened. The attacks resulted in significant loss of life and widespread global consequences.