NEW YORK -- 5:45 a.m. - Hijackers pass through security in Portland, Maine, and board a flight to Boston, where they connect to American Airlines Flight 11.
6:00 a.m. - Polling stations open, as September 11 was a primary election day in New York City.
7:59 a.m. - Flight 11 takes off from Boston for Los Angeles. Eleven crew members, 76 passengers, and five hijackers are on board.
CLICK HERE for more Eyewitness News reflections, photos and stories marking the anniversary of 9/11
8:15 a.m. - Flight 175 takes off from Boston for Los Angeles. Nine crew members, 51 passengers, and five hijackers are on board.
8:19 a.m. - Flight 11 crew members alert ground personnel that a hijacking is underway. Shortly before, one hijacker stabbed a passenger, Daniel Lewin, who was seated in front of him. Officials speculate that Lewin may have tried to stop the hijackers and was likely the first victim of the attacks.
8:20 a.m. - American Airlines Flight 77, en route to Los Angeles, takes off from Washington, D.C. Six crew members, 53 passengers, and five hijackers are on board.
8:24 a.m. - Attempting to communicate with passengers, a hijacker contacts air traffic control, unwittingly alerting controllers to the attacks.
8:37 a.m. - Boston air traffic control alerts the military. Air National Guard jets in Massachusetts are mobilized to follow Flight 11.
Related: In memory of Don DiFranco, WABC engineer killed on 9/11
8:42 a.m. San Francisco-bound United Airlines Flight 93 takes off at Newark following a delay. Seven crew members, 33 passengers, and four hijackers are on board.
8:46 a.m. - Flight 11 crashes into floors 93 through 99 of the North Tower.
8:50 a.m. - President George W. Bush is alerted. His advisors assume this is a tragic accident.
8:55 a.m. - The South Tower is declared secure.
8:59 a.m. - Port Authority police order the evacuation of both towers. A minute later, the order is expanded to the entire World Trade Center complex.
9:00 a.m. - A flight attendant aboard Flight 175 alerts air traffic control that a hijacking is underway.
Related: 9/11 attacks by the numbers
9:03 a.m. - Flight 175 crashes into floors 77 through 85 of the South Tower.
9:05 a.m. - President Bush learns that a second plane has crashed into the World Trade Center. Twenty-five minutes later, he addresses Americans, saying that "terrorism against our nation will not stand."
9:05 a.m. - Flight 77 passenger Barbara Olson calls her husband, U.S. Solicitor General Theodore Olson, who alerts other federal officials of the hijacking.
9:36 a.m. - Secret Service agents evacuate Vice President Dick Cheney to the Presidential Emergency Operations Center beneath the White House.
9:37 a.m. - American Airlines Flight 77 crashes into the Pentagon. The crash and fire kill 59 on the plane and 125 on the ground.
9:42 a.m. - The FAA grounds all flights.
PHOTOS: 9/11 attacks on the World Trade Center in New York City
9:45 a.m. - The White House and U.S. Capitol are evacuated.
9:59 a.m. - The South Tower collapses in 10 seconds after burning for 56 minutes. More than 800 people in and around the building are killed.
10:03 a.m. - United Airlines Flight 93 crashes near Shanksville, Pennsylvania after passengers and crew storm the cockpit. Forty people on board, excluding the hijackers, perish.
10:15 a.m. - The Pentagon's outer ring collapses.
10:28 a.m. - The North Tower collapses after burning for 102 minutes. More than 1,600 in and around the building are killed.
Photos: The aftermath of 9/11
11:02 a.m. - New York City Mayor Rudy Giuliani orders the evacuation of Lower Manhattan.
12:16 p.m. - The last flight still in the air above the continental United States lands.
12:30 p.m. - A group of 14 survivors are emerge from a North Tower stairwell.
3:00 p.m. - A survivor, Pasquale Buzzelli, is rescued from the rubble of the North Tower.
5:20 p.m. - After burning for hours, 7 World Trade Center collapses, There are no casualties.
8:30 p.m. - President Bush addresses the nation from the White House, assuring Americans that a search is underway for "those who are behind these evil acts."
10:30 p.m. - Rescuers locate and extract two PAPD officers injured but alive in debris of the World Trade Center.
* Get Eyewitness News Delivered
* Follow us on YouTube
* More local news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
Submit a News Tip
9/11 Timeline: How the September 11 attacks unfolded
More TOP STORIES News