World Trade Center site
On the morning of September 11, 2001, Islamic terrorists affiliated with Al-Qaeda hijacked American Airlines Flight 11 and United Airlines Flight 175, both which were en route to Los Angeles, and intentionally crashed them into the two main towers of the World Trade Center. The towers collapsed within two hours of the collisions. 2,606 people, including 2,192 civilians, 71 law enforcement officers, and 343 firefighters, who were in the towers and in the surrounding area died in the attacks, as well as 147 civilians and the 10 hijackers aboard the two airliners. After the collapse of the World Trade Center, hospital workers and law enforcement officers began referring to the World Trade Center site as "Ground Zero".
Responsibility for the September 11 attacks
According to interviews by Al-Jazeera as well as United States interrogations of al-Qaeda members Ramzi bin al-Shibh and Khalid Shaikh Mohammed (captured in 2002 and 2003 respectively), Khalid Sheikh Mohammed was the instigator and prime organizer of the attacks. Bin al-Shibh may have been picked as a hijacker but he failed to get into the United States.