Exactly 184 people died in the Pentagon and on American Airlines Flight 77 on September 11, 2001. In response to this terrorist attack, the Department of Defense established the Pentagon Force Protection Agency. The agency absorbed the Pentagon's police force and expanded on its role to provide law enforcement and security for the Defense department's headquarters. The agency is tasked with protecting lives, facilities, information, and equipment. It prepares for, detects, responds to, and prevents terrorist attacks, including chemical, biological, radiological, and nuclear offenses. It protects the Pentagon's 280 acres and its 26,000 military and civilian employees and non-defense support personnel.