The September 11 attacks (often referred to as 9/11) were a series of co-ordinated suicide attacks by the terrorist organisation al-Qaeda upon the United States in 2001. Four passenger jet airliners were hijacked with full loads of fuel and two were intentionally crashed into the Twin Towers of the World Trade Center in New York City, killing everyone on board and many working in the building. Including the crash into the Pentagon in Washington, 2,988 victims were murdered in the attacks.
