http://www.history.com/photos/9-11-world-trade-center On September 11, 2001 terrorists hijacked planes and crashed them into the World Trade Center's Twin Towers. The towers collapsed and thousands of people were killed. en Copyright 2013, History.com Mon, 20 May 2013 04:00:00 GMT History.com 2013-05-20T04:00:00Z en Copyright 2013, History.com http://www.history.com/photos/9-11-world-trade-center/photo1 An aerial view of the World Trade Center towers before the attacks of September 11, 2001. http://www.history.com/photos/9-11-world-trade-center/photo1 http://www.history.com/photos/9-11-world-trade-center/photo2 A series of images showing the planes hitting the towers on September 11, 2001. http://www.history.com/photos/9-11-world-trade-center/photo2 http://www.history.com/photos/9-11-world-trade-center/photo3 A rescue worker helps people evacuate the World Trade Center area after the collapse of the towers. http://www.history.com/photos/9-11-world-trade-center/photo3 http://www.history.com/photos/9-11-world-trade-center/photo4 A piece of the outer frame of the building is all that is left standing in the ruined base of the World Trade Center. http://www.history.com/photos/9-11-world-trade-center/photo4 http://www.history.com/photos/9-11-world-trade-center/photo5 An NYPD patrol car, destroyed by falling debris from the collapse of the World Trade Center, sits amid the rubble at ground zero on the night of September 11, 2001. http://www.history.com/photos/9-11-world-trade-center/photo5 http://www.history.com/photos/9-11-world-trade-center/photo6 A firefighter uses a thermal imaging device to look for signs of life during the morning of September 12, about 24 hours after the first airplane hit the World Trade Center. http://www.history.com/photos/9-11-world-trade-center/photo6 http://www.history.com/photos/9-11-world-trade-center/photo7 MTA workers assist in rescue and recovery efforts at the site of the World Trade Center in the aftermath of the September 11, 2001 attacks. http://www.history.com/photos/9-11-world-trade-center/photo7 http://www.history.com/photos/9-11-world-trade-center/photo8 An office space is destroyed and covered with debris from the collapse of the World Trade Center. http://www.history.com/photos/9-11-world-trade-center/photo8 http://www.history.com/photos/9-11-world-trade-center/photo9 New York City Mayor Rudolph Giuliani at the funeral for New York City Fire Department Chief Peter J. Ganci. Chief Ganci, a 33-year veteran of the New York City Fire department, and its highest ranking uniformed officer, was killed during the collapse of the World Trade Center. http://www.history.com/photos/9-11-world-trade-center/photo9 http://www.history.com/photos/9-11-world-trade-center/photo10 In the days after 9/11 families of missing people put up thousands of posters with photos and descriptions of their loved ones. Parks like Union Square became gathering points for people to come together, share stories and lend support. http://www.history.com/photos/9-11-world-trade-center/photo10 http://www.history.com/photos/9-11-world-trade-center/photo11 Flyer asking for help in locating Matt Heard, a missing Morgan Stanley worker, surrounded by candles at a memorial for victims of the September 11, 2001 terrorist attacks on the World Trade Center. http://www.history.com/photos/9-11-world-trade-center/photo11 http://www.history.com/photos/9-11-world-trade-center/photo12 'God Bless America' sign hung on the Brooklyn Heights promenade, which overlooks the transformed skyline of lower Manhattan. The sign is part of an impromptu memorial, one of many that sprung up in the days following the terrorist attacks of September 11, 2001. http://www.history.com/photos/9-11-world-trade-center/photo12 http://www.history.com/photos/9-11-world-trade-center/photo13 Mourners at a funeral for one of the New York City firefighters killed on September 11, 2001. http://www.history.com/photos/9-11-world-trade-center/photo13 http://www.history.com/photos/9-11-world-trade-center/photo14 A statue becomes a shrine to fallen firefighters who died during the collapse of the World Trade Center buildings. http://www.history.com/photos/9-11-world-trade-center/photo14 http://www.history.com/photos/9-11-world-trade-center/photo15 The wreckage of the World Trade Center smoulders in this aerial view of Manhattan taken September 15, 2001. http://www.history.com/photos/9-11-world-trade-center/photo15 http://www.history.com/photos/9-11-world-trade-center/photo16 An aerial view of the remains of the Twin Towers and World Trade Center, eight days after they were destroyed by he terrorist attacks of September 11, 2001. The site soon became known as Ground Zero. http://www.history.com/photos/9-11-world-trade-center/photo16 http://www.history.com/photos/9-11-world-trade-center/photo17 Pedestrians walk past a sign announcing the opening of the 9/11 Memorial Preview Site in front of Ground Zero, in New York, August 2009. The 9/11 Memorial Preview Site will provide the public with the opportunity to learn about the National September 11 Memorial and Museum. http://www.history.com/photos/9-11-world-trade-center/photo17 http://www.history.com/photos/9-11-world-trade-center/photo18 One of the two Tribute in Light columns at Ground Zero, memorials to the victims of the September 11th terrorist attacks on the World Trade Center's Twin Towers. http://www.history.com/photos/9-11-world-trade-center/photo18