Pictured here is the Tower of Voices, a 93-foot-tall monument to the passengers and crew on Flight 93. Hijackers seized the plane shortly after it left Newark, New Jersey, on September 11, 2001. As travelers onboard learned of the coordinated attacks in New York and Washington, DC, a group of passengers and flight crew attempted to wrest control of the plane. The aircraft crashed into a field near Shanksville, Pennsylvania, killing everyone on board. It was the only one of the four hijacked planes that didn’t hit its intended target.