World Trade Center (2001–present)
The buildings are among many created by the World Trade Centers Association. The original World Trade Center featured the landmark Twin Towers, which opened in 1973, and were the tallest buildings in the world at the time of their completion. They were destroyed on the morning of September 11, 2001, when al-Qaeda-affiliated hijackers flew two Boeing 767 jets into the complex in a coordinated act of terrorism. The attacks on the World Trade Center killed 2,753 people. The resulting collapse of the World Trade Center caused structural failure in the surrounding buildings as well. The process of cleaning up and recovery at the World Trade Center site took eight months, after which rebuilding of the site commenced.
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.