Khalid Shaikh Mohammed, the mastermind of the September 11 terror attacks on the United States continues to await trial even after two decades that left around 2,977 people dead.

19 terrorists of Al-Qaeda hijacked four commercial planes and carried out attacks in different locations in the USA. The hijackers crashed the first two planes into the twin towers of the World Trade Center in New York City, and the third plane into the Pentagon (the headquarters of the American military) in Arlington, Virginia. The fourth plane was intended to hit a federal government building in Washington, DC, but crashed in a field.