World Trade Center site
On the morning of September 11, 2001, Islamic terrorists affiliated with Al-Qaeda hijacked American Airlines Flight 11 and United Airlines Flight 175, both which were en route to Los Angeles, and intentionally crashed them into the two main towers of the World Trade Center. The towers collapsed within two hours of the collisions. 2,606 people, including 2,192 civilians, 71 law enforcement officers, and 343 firefighters, who were in the towers and in the surrounding area died in the attacks, as well as 147 civilians and the 10 hijackers aboard the two airliners. After the collapse of the World Trade Center, hospital workers and law enforcement officers began referring to the World Trade Center site as "Ground Zero".
United Airlines Flight 93
After the hijackers took control of the plane, several passengers and flight attendants learned from phone calls that suicide attacks had already been made by hijacked airliners on the World Trade Center in New York City and the Pentagon in Arlington County, Virginia. Many of the passengers then attempted to regain control of the aircraft from the hijackers. During the struggle, the plane crashed into a field near a reclaimed strip mine in Stonycreek Township, near Indian Lake and Shanksville, about southeast of Pittsburgh and northwest of Washington, D.C. A few people witnessed the impact from the ground, and news agencies began reporting the event within an hour.