Who was behing september 11th?

The September 11, 2001 attacks were orchestrated by the extremist group al-Qaeda, led by Osama bin Laden. Nineteen hijackers, primarily from Saudi Arabia, carried out coordinated suicide attacks using commercial airplanes to target the World Trade Center in New York City and the Pentagon in Virginia. The attacks resulted in the deaths of nearly 3,000 people and prompted significant changes in U.S. and global security policies.