PENTTBOM

PENTTBOM (sometimes spelled as PENTTBOMB) was the FBI's investigation into the terrorist attacks against the United States on September 11, 2001 (9/11), in which 19 members of al-Qaeda hijacked four U.S. commercial airliners in an attempt to crash them into national landmarks. The name is short for "Pentagon/Twin Towers Bombs", the "bombs" being three planes that had hit the Pentagon in Virginia, and the Twin Towers (1 and 2 World Trade Center) in New York City. The fourth plane crashed in Pennsylvania following passenger intervention. It was the largest investigation in the FBI's history, in total involving 7,000 employees, including 4,000 special agents. They conducted 180,000 interviews and reviewed millions of pages of documents, and just within the first few months after the attacks, looked into more than 250,000 leads. Thousands of agents were dispatched to other countries for field research.