The September 11 attacks (also called 9/11), were four terrorist attacks against the United States of America. They all happened on the morning of Tuesday, September 11, 2001. The attacks killed 3,000 people, including the 19 attackers, making it the deadliest terrorist attack in history. They caused more than $10 billion in damage to infrastructure.<ref name="PEARL9/11"></ref> They were carried out by the Islamic terrorist group al-Qaeda. They used passenger airplanes to destroy famous buildings by flying the planes into them. There were two attacks in New York City and one in Arlington, Virginia. The fourth attack did not work and the plane crashed in a field near Shanksville, Pennsylvania.