pentagon 8

On September 11, 2001, the 60th anniversary of The Pentagon's groundbreaking, a team of five al-Qaeda affiliated hijackers took control of American Airlines Flight 77, en route from Washington Dulles International Airport to Los Angeles International Airport, and deliberately crashed the Boeing 757 airliner into the western side of the Pentagon at 9:37 am EDT as part of the September 11 attacks. All 64 people on the airliner were killed as were 125 people who were in the building. The impact of the plane severely damaged the structure of the building and caused its partial collapse.^[39] At the time of the attacks, the Pentagon was under renovation and many offices were unoccupied, resulting in fewer casualties. Only 800 of 4,500 people who would have been in the area were there because of the work. Furthermore the area hit, on the side of the Heliport Entrance facade, was the section best prepared for such an attack. The renovation there, improvements which resulted from the Oklahoma City bombing, had nearly been completed.^[40][41][42]

It was the only area of the Pentagon with a sprinkler system, and it had been reconstructed with a web of steel columns and bars to withstand bomb blasts. The steel reinforcement, bolted together to form a continuous structure through all of the Pentagon's five floors, kept that section of the building from collapsing for 30 minutes—enough time for hundreds of people to crawl out to safety. The area struck by the plane also had blast-resistant windows—2 inches thick and 2,500 pounds each—that stayed intact during the crash and fire. It had fire doors that opened automatically and newly built exits that allowed people to get out.^[40]