Hijacked American Airlines Flight 77 crashes into the Pentagon

On September 11, 2001, at approximately 9:37 a.m. Eastern Daylight Time, five al-Qaeda-affiliated hijackers deliberately crashed American Airlines Flight 77 into the western side of the Pentagon. The Boeing 757 had departed Washington Dulles International Airport for Los Angeles before being hijacked. The collision caused extensive structural damage, fires, and the partial collapse of the building's outer section. The attack killed 184 victims, including 125 people inside the Pentagon and 59 passengers and crew members aboard the aircraft, excluding the five hijackers. At the time, the Pentagon was undergoing a major renovation, and many offices in the affected section were unoccupied. According to the document, approximately 800 people were present in the impacted area, compared with its usual occupancy of about 4,500. Recent safety improvements included blast-resistant windows, steel structural reinforcement, fire doors, sprinkler systems, and additional emergency exits. These measures helped limit the extent of structural collapse and allowed some occupants to evacuate. The attack occurred exactly sixty years after construction of the Pentagon began on September 11, 1941, and became one of the defining events in the building's history.