In the span of 90 minutes on the morning of September 11, 2001, two hijacked commercial airliners struck the World Trade Center, causing collapses that erased a landmark from the city's skyline and buried scores of victims. Following is a timeline of a horrific day in the history of the city and nation:
8:46 a.m. A commercial airliner flies directly into the upper floors of the north tower of the World Trade Center, causing a fireball explosion and littering debris and body parts below. The airliner is American Airlines Flight 11 from Boston to Los Angeles, carrying 92 people on board.
9:03 a.m. A second plane, United Airlines Flight 175 from Boston to Los Angeles, crashes into the south tower with 65 passengers and crew. Thousands of people on the ground and many more watching live news reports witness the second plane plow into the building while smoke is still billowing into the air from the first attack.
9:30 a.m. At an appearance in Florida, the president calls the crashes "an apparent terrorist attack" and a "national tragedy."
9:38 a.m. A third hijacked aircraft - American Airlines Flight 77 carrying 64 people from Washington to Los Angeles - crashes into the Pentagon, causing the partial collapse of one of the five sides of the nation's military headquarters. In response, government buildings in the nation's capitol, including the White House and the Capitol, are evacuated. All airports in the U.S. are also closed and all commercial flights are simultaneously grounded for the first time in the nation's history.
9:59 a.m. About an hour after the initial impact, Two World Trade Center, the second tower to be hit, buckles and then completely collapses onto itself. Thousands of people run for cover as falling debris chases them up the streets of Lower Manhattan.
10:28 a.m. One World Trade Center falls less than half an hour after the first collapse, after another explosion rocks the damaged tower. Authorities begin the evacuation of all of Lower Manhattan in a mass exodus of workers and residents.
10:40 a.m. United Airlines Flight 93, under the control of hijackers, crashes about 80 miles southeast of Pittsburgh, Pennsylvania, apparently before reaching the terrorists' intended target. The plane was carrying 45 people from Newark to San Francisco.
12:58 p.m. Afghanistan's Taliban rulers condemn the attacks in New York and Washington, saying accused terrorist mastermind Osama bin Laden - a fugitive from U.S. justice hiding within their borders - was not behind them. American authorities still consider bin Laden a prime suspect.
1:02 p.m. The president, who was temporarily taken to a Louisiana Air Force base instead of Washington due to safety concerns, vows to find and punish those responsible for the tragedy, saying, "We will do what it takes, whatever is necessary to secure America and Americans."
2:30 p.m. With a massive search and rescue operation underway, Mayor Rudolph Giuliani says the death toll from the attacks will be "more than any of us can bear."
5:20 p.m. Seven World Trade Center collapses, succumbing to a fire that had raged most of the day. The 47-story building next to towers was home to the Office of Emergency Management's multi-million dollar bunker, which would have served as the emergency coordination center had the building not become unstable.
6:00 p.m. Cruise missile are fired at the Afghanistan capital of Kabul and ignite a fuel dump there. The Pentagon later denies any involvement in the attacks and and a rebel group fighting the Taliban in a long civil war claims responsibility.
8:30 p.m. The president, now back in Washington, addresses the nation from the Oval Office. He promises to commit the full resources of the nation's intelligence and law enforcement communities to find the terrorists and bring them to justice.
10:30 p.m. Mayor Rudolph Giuliani says that some people may be alive in the rubble of the Trade Center, in addition to the dozen or so survivors who have already been pulled from the wreckage after being buried there. In the 14 hours that follow, emergency crews pull two Port Authority police officers and a female Trade Center worker from the debris.