Twelve years after the Sept. 11 attacks, these images still resonate, reminding of the absolute physical and emotional devastation that so many people experienced that day.
(Many of the photos below contain graphic content.)
In this Sept. 11, 2001 file photo, United Airlines Flight 175 closes in on World Trade Center Tower 2 in New York, just before impact. (AP Photo/Carmen Taylor, File)
In this Sept. 11, 2001 file photo, United Airlines Flight 175 closes in on World Trade Center Tower 2 in New York, just before impact. (AP Photo/William Kratzke)
In this September 11, 2001 file photo, smoke pours off World Trade Center Tower 1 as flames explode from Tower 2 as it is struck by United Airlines Flight 175, after terrorists crashed hijacked airliners into the buildings. (AP Photo/Chao Soi Cheong)
A fiery blasts rocks the south tower of the World Trade Center as the hijacked United Airlines Flight 175 from Boston crashes into the building September 11, 2001 in New York City. (Photo by Spencer Platt/Getty Images)
People stand on a dirt mound at the Vince Lombardi Service Area on the New Jersey Turnpike as they watch smoke billowing from the remains of the World Trade Center in New York after planes crashed into each of the twin towers Tuesday morning, Sept. 11, 2001. (AP Photo/Gene Boyars)
A person falls from the north tower of New York's World Trade Center Tuesday Sept. 11, 2001 after terrorists crashed two hijacked airliners into the World Trade Center and brought down the twin 110-story towers. (AP Photo/Richard Drew)
People hang out of broken windows of the North Tower of the World Trade Center in New York on the morning of Sept. 11, 2001. (AP Photo/Amy Sancetta)
The south tower of New York's World Trade Center collapses Tuesday Sept. 11, 2001. (AP Photo/Richard Drew)
Pedestrians on Park Row flee the area of the World Trade Center as the center's south tower collapses following the terrorist attack on the New York landmark Tuesday, Sept. 11, 2001. (AP Photo/Amy Sancetta)
This 11 September 2001 file photo shows Marcy Borders covered in dust as she takes refuge in an office building after one of the World Trade Center towers collapsed in New York. Borders was caught outside on the street as the cloud of smoke and dust enveloped the area. The woman was caught outside on the street as the cloud of smoke and dust enveloped the area. (STAN HONDA/AFP/Getty Images)
People run from the collapse of one of the twin towers of New York's World Trade Center in this Sept. 11, 2001, file photo. (AP Photo/FILE/Suzanne Plunkett)
Survivors of the World Trade Center terrorist attacks make their way through smoke, dust and debris on Fulton St., about a block from the collapsed towers, Tuesday, Sept. 11, 2001 in New York. (AP Photo/Gulnara Samoilova)
A tennis shoe and debris, photographed one block from the World Trade Center, are coated with dust after the collapse of the twin towers in this photo taken Tuesday, Sept. 11, 2001 in New York. Paper records, documents and correspondence from the towers littered the streets following the collapse. (AP Photo/Mark Lennihan)
The rubble of the World Trade Center smoulders following a terrorist attack 11 September 2001 in New York. (ALEX FUCHS/AFP/Getty Images)
View of smoke and flames at the Pentagon shortly after a hijacked jetliner was crashed into building, Washington DC, September 11, 2001. The crash was part of a coordinated, terrorist attack on the United States that also felled both towers of the World Trade Center in New York. (Photo by PhotoQuest/Getty Images)
Mounted police make their way along an access road leading to the crash site of United Airlines Flight 93 through the early morning fog 12 September 2001 in Shanksville, Pennsylvania. The plane was hijacked and crashed killing all 45 on board. (DAVID MAXWELL/AFP/Getty Images)
Photographs of missing people from the 11 September 2001 World Trade Center attack sit on a television truck outside Bellevue Hospital in New York 12 September, 2001 where family members and friends stand vigil in hopes of getting information from authorities and help from media exposure. (JOHN MOTTERN/AFP/Getty Images)
A firefighter breaks down after the World Trade Center buildings collapsed September 11, 2001 after two hijacked airplanes slammed into the twin towers in a terrorist attack. (Photo by Mario Tama/Getty Images)
(Photo by Corey Sipkin/NY Daily News Archive via Getty Images)
Firefighter covered with ash after World Trade Center collapsed in terrorist attack. (Photo by Thomas Monaster/NY Daily News Archive via Getty Images)
An injured man is tended to after a terrorist attack on the World Trade Center. (Photo By: Susan Watts/NY Daily News via Getty Images)
An injured man waits for help as others take refuge in a bank near the World Trade Center towers 11 September, 2001, in New York. (STAN HONDA/AFP/Getty Images)
An American flag flies in the foreground as one of the World Trade Center towers burns in the background 11 September 2001 in New York. Two hijacked airplanes crashed into the two landmark skyscrapers. (DOUG KANTER/AFP/Getty Images)
People seek refuge inside a bank building after the first tower of the World Trade Center collapsed. (Photo by Corey Sipkin/NY Daily News Archive via Getty Images)
Firefighter Kevin Shea of Ladder 35 lies semi conscious in debris field with Firefighter Ritchie Nogan of 113 standing over him. Shea was the only survivor of his unit. He was carried out by Nogan, two EMS workers and photographer Todd Maisel. (Photo by Todd Maisel/NY Daily News Archive via Getty Images)
This file photo taken on September 11, 2001 shows a man standing in the rubble, and calling out asking if anyone needs help, after the collapse of the first World Trade Center Tower in New York City. (DOUG KANTER/AFP/Getty Images)
Correction: An earlier version of this story incorrectly stated the flight name of the plane that crashed into the second World Trade Center tower. It was United Airlines Flight 175.
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The four airplanes that were hijacked on 9/11 <a href="http://www.reuters.com/article/2011/08/10/idUS221159963020110810" target="_hplink">began</a> taking off at 7:59 a.m. The first to depart was American Airlines Flight 11, a Boeing 767 that left Boston's Logan International Airport for Los Angles with 92 people on board. At 8:14 a.m., United Airlines Flight 175 -- a Boeing 767 with 65 passengers on board -- also left Logan for Los Angeles. American Airlines Flight 77 left Washington Dulles International Airport at 8:20 a.m. The plane, a Boeing 757 with 64 people on board, was bound for Los Angeles. Finally, at 8:42 a.m., United Airlines Flight 93 departed from Newark International Airport. The Boeing 757, which had 44 passengers that morning, was bound for San Francisco.
The first crash <a href="http://www.nysm.nysed.gov/wtc_timeline/zoomify.html" target="_hplink">occurred</a> at 8:46 a.m. when Flight 11 hit the north tower of New York's World Trade Center. According to the <a href="http://www.9-11commission.gov/report/index.htm" target="_hplink">9/11 Commission Report</a>, two flight attendants contacted American Airlines as the plane was being hijacked to provide details of the emergency. They reported the use of Mace or a similar spray, several stabbings and a bomb threat. The last known communication from the plane came when flight attendant Madeline "Amy" Sweeney, on the phone with American Flight Services manager Michael Woodward, said, "Oh my God we are way too low."
The second crash happened at 9:03 a.m., when Flight 175 hit the south tower of the World Trade Center. The last communication made with air traffic control was made at 8:42 a.m., but passengers were able to provide details of the flight by contacting their families by phone. <a href="http://timeline.national911memorial.org#/Explore/2/Entry/533" target="_hplink">Brian Sweeney</a> called his wife, Julie, to tell her the plane had been hijacked, and Peter Hansen <a href="http://www.9-11commission.gov/report/index.htm" target="_hplink">told</a> his father, Lee, "I think they intend to go to Chicago or someplace and fly into a building."
President George W. Bush <a href="http://timeline.national911memorial.org/#/Explore/2" target="_hplink">learned</a> of the attacks at 9:05 a.m. while sitting in a second grade classroom at an elementary school in Sarasota, Florida. White House Chief of Staff Andrew Card informed him of the attacks, whispering into his ear during the students' reading lesson. Bush recently <a href="http://channel.nationalgeographic.com/channel/community/blogs/ngc/_george-w-bush-911-interview" target="_hplink">shared</a> his memories of that day with <i>National Geographic</i>. When he received news of the first plane crash at 8:50 a.m. -- just before entering the classroom -- he thought it was "a light aircraft, and my reaction was, man, the weather was bad or something extraordinary happened to the pilot." It wasn't until Card informed him of the second plane that Bush knew America was under attack.
In an <a href="http://www.youtube.com/watch?v=QP1K84iRZPo" target="_hplink">address</a> from Emma Booker Elementary School in Sarasota, Florida, President Bush called the attacks "a national tragedy" and "an apparent terrorist attack on our country." "I have spoken to the vice president, to the governor of New York, to the director of the FBI, and have ordered that the full resources of the federal government go to help the victims and their families, and to conduct a full-scale investigation to hunt down and to find those folks who committed this act," Bush said. "Terrorism against our nation will not stand."
At 9:36 a.m., Secret Service agents <a href="http://timeline.national911memorial.org/#/Explore/2" target="_hplink">evacuated</a> Vice President Dick Cheney and his aides from his office to the Presidential Emergency Operations Center, a Cold War-era bunker beneath the White House.
Flight 77 crashed into Pentagon at 9:37 a.m. The 9/11 Commission Report tells how passenger Barbara Olson <a href="http://www.gpoaccess.gov/911/index.html" target="_hplink">called</a> her husband Ted -- the solicitor general of the United States -- to inform him of the attacks. She reported that the flight had been taken over and that the aircraft was "flying low over houses." A few minutes later, air traffic controllers at Dulles International Airport observed plane on their radar traveling at "a high rate of speed." Officials from Ronald Reagan Washington National Airport warned the Secret Service of the aircraft shortly before Flight 77 hit the Pentagon.
At 9:45 a.m. -- minutes after Flight 77 crashed into the Pentagon -- the White House and U.S. Capitol were <a href="http://timeline.national911memorial.org/#/Explore/2" target="_hplink">evacuated</a>.
After burning for 56 minutes, the south tower of the World Trade Center <a href="http://timeline.national911memorial.org/#/Explore/2" target="_hplink">collapsed</a> at 9:59 a.m. The fall, which killed approximately 600 workers and first responders, lasted 10 seconds.
The fourth hijacked plane crashed at 10:03 a.m. in a field in Shanksville, Pennsylvania. The 9/11 Commission Report <a href="http://www.gpoaccess.gov/911/pdf/sec1.pdf" target="_hplink">says</a> several passengers made calls from the plane and received word of the other hijackings. Upon hearing the news that major cities were being targeted, the passengers decided to revolt: <blockquote>Five calls described the intent of passengers and surviving crew members to revolt against the hijackers. According to one call, they voted on whether to rush the terrorists in an attempt to retake the plane. They decided, and acted.<br><br>At 9:57, the passenger assault began. Several passengers had terminated phone calls with loved ones in order to join the revolt. One of the callers ended her message as follows:"Everyone's running up to first class. I've got to go. Bye."</blockquote> <a href="http://timeline.national911memorial.org/#/Explore/2" target="_hplink">According</a> to the 9/11 Memorial, the hijackers deliberately crashed in a field to prevent passengers from retaking the airplane. The crash site in Shanksville is approximately 20 minutes flying time from Washington, D.C.
At 10:28 a.m., after burning for 102 minutes, the north tower of New York's World Trade Center <a href="http://timeline.national911memorial.org/#/Explore/2" target="_hplink">collapsed</a>, killing approximately 1,400 people.
New York City Mayor Rudy Giuliani <a href="http://www.nysm.nysed.gov/wtc_timeline/zoomify.html" target="_hplink">ordered</a> an evacuation of lower Manhattan at 11:02 a.m., alerting everyone south of Canal Street to get out.
At 1:04 p.m., after all American air space had been cleared, President Bush <a href="http://www.nysm.nysed.gov/wtc_timeline/zoomify.html" target="_hplink">addressed </a>the nation from Barksdale Air Force Base in Louisiana, informing citizens that the U.S. military "at home and around the world is on high alert status." "Make no mistake, the United States will hunt down and punish those responsible for these cowardly acts," Bush <a href="http://www.youtube.com/watch?v=bwgqmaeV7o0" target="_hplink">said</a>.
Hours after the attacks that morning, the 47-story 7 World Trade Center building <a href="http://www.nysm.nysed.gov/wtc_timeline/zoomify.html" target="_hplink">collapsed</a> from ancillary damage. No one was in the building at the time.
President Bush gave his final <a href="http://articles.cnn.com/2001-09-11/us/bush.speech.text_1_attacks-deadly-terrorist-acts-despicable-acts?_s=PM:US" target="_hplink">address</a> of the day from the White House at 8:30 p.m. From the Oval Office, the president informed Americans that he had implemented federal emergency response plans, noting emergency teams and the military were already at work: <blockquote>Today, our fellow citizens, our way of life, our very freedom came under attack in a series of deliberate and deadly terrorist acts.<br><br>The victims were in airplanes or in their offices -- secretaries, businessmen and women, military and federal workers. Moms and dads. Friends and neighbors.<br><br>Thousands of lives were suddenly ended by evil, despicable acts of terror.<br><br>The pictures of airplanes flying into buildings, fires burning, huge structures collapsing, have filled us with disbelief, terrible sadness and a quiet, unyielding anger.<br><br>These acts of mass murder were intended to frighten our nation into chaos and retreat. But they have failed. Our country is strong. A great people has been moved to defend a great nation.</blockquote>