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".
Kroll Inc.
Kroll were responsible for revamping security at the World Trade Center after the 1993 World Trade Center bombing. They also took on responsibility for security at Chicago's Sears Tower following the September 11, 2001 attacks.
Just prior to the September 11 attacks, Kroll Inc., with the guidance of Jerome Hauer, at the time the Managing director of their Crisis and Consulting Management Group,
hired former FBI special investigator John P. O'Neill, who specialized in the Al-Qaeda network held responsible for the 1993 bombing, to head the security at the WTC complex. O'Neill died in the attacks.