A plaque dedicated to United Airlines Flight 93 is unveiled at the East Front Lobby of the Capitol Hill in Washington, DC, on September 9, 2009. Flight 93 was hijacked on September 11, 2001 and crashed in Pennsylvania. Getty Images logo Getty Images 29 months ago

A plaque dedicated to United Airlines Flight 93 is unveiled at the East Front Lobby of the Capitol Hill in Washington, DC, on September 9, 2009. Flight 93 was hijacked on September 11, 2001 and crashed in Pennsylvania.