As a proper noun phrase, "September 11th Pentagon attack" refers to a specific, singular event. It functions as the subject or object within a sentence, naming the act of terrorism that occurred on that date at that location. The core noun is "attack," which is modified by the adjectival phrases "September 11th" (specifying the date) and "Pentagon" (specifying the location), creating a compound noun that designates a historically significant incident.
This event was one of four coordinated terrorist attacks conducted by the Islamic extremist group al-Qaeda on September 11, 2001. Five hijackers took control of American Airlines Flight 77, a Boeing 757, after its departure from Washington Dulles International Airport. They deliberately crashed the aircraft into the western side of the Pentagon in Arlington, Virginia, at 9:37 AM EDT. The impact and the resulting jet-fuel-fed fire caused a partial collapse of the building's structure.
The strike on the headquarters of the U.S. Department of Defense was a direct assault on a symbol of American military power. The incident resulted in 184 fatalities on the ground and aboard the aircraft, in addition to the five perpetrators. This act of war on U.S. soil was a critical catalyst for the subsequent launch of the global War on Terror, fundamentally altering U.S. foreign policy, national security architecture, and aviation security protocols worldwide.
