An informative poster detailing the events of the September 11, 2001, terrorist attacks, highlighting the hijackings, the collapse of the World Trade Center, and the crash of Flight 93.
The image displays a detailed informational poster titled "What Happened on September 11?" describing the events of the 9/11 terrorist attacks, including the hijackings of four commercial airplanes, the attacks on the World Trade Center and the Pentagon, and the crash of Flight 93 in Pennsylvania. The poster includes historical photographs of the planes, the Twin Towers, and related text.