Terrorist attacks on the United States. Timeline of events (Eastern Daylight Time):
American Airlines flight 11, flying from Boston to Los Angeles with 92 people on board, crashes into the north tower of the World Trade Center in New York City, ripping into multiple floors and igniting a massive fire.
Firefighters and emergency crews begin heading for the Trade Center.
Bridges and tunnels leading to Lower Manhattan are closed to all but emergency vehicles.
United Airlines flight 175, flying from Boston to Los Angeles with 65 people on board, crashes into the south tower of the World Trade Center, damaging multiple floors and bursting into flames.
The Federal Aviation Administration shuts down every airport in the New York City area.
The Port Authority of New York and New Jersey closes every bridge and tunnel in the New York area.
From Florida, President George W. Bush announces the country has suffered an "apparent terrorist attack," and pledges that the United States will hunt down the responsible parties.
American Airlines flight 77, flying from Dulles Airport in Washington, D.C. to Los Angeles with 64 people on board, crashes into the Pentagon, in northern Virginia, and explodes into flames.
The Federal Aviation Administration (F.A.A.) halts all flight operations at American airports, and orders every commercial airliner to land immediately, marking the first time in U.S. history that air traffic nationwide has been suspended.
In Washington, D.C., workers are evacuated from the U.S. Capitol and the White House.
The south tower of the World Trade Center collapses.
An emergency operator in Pennsylvania receives a call from a passenger on United Airlines flight 93, flying from Newark to San Francisco with 45 people aboard, stating the plane is being hijacked.
Damage from the plane crash causes part of the Pentagon to collapse.
United Airlines flight 93 crashes to the ground in Somerset County, Pennsylvania, southeast of Pittsburgh, heroically brought down by its own passengers after hearing about the attacks on the World Trade Center. Officials later speculate that the plane's hijackers had intended to attack the White House or the Capitol.
In New York City, the United Nations is evacuated.
The F.A.A. diverts all transatlantic aircraft flying to the U.S., sending them to Canada.
The north tower of the World Trade Center collapses.
New York mayor Rudolph Giuliani orders Lower Manhattan to be evacuated.
With the U.S. military on nuclear alert, President Bush is taken to Barksdale Air Force Base in Louisiana.
From Barksdale Air Force Base, President Bush states that the nation is taking appropriate security measures, and the U.S. military is on high alert worldwide. He asks Americans to pray for the victims of the attacks and says America "will hunt down and punish those responsible for these cowardly acts." The President will soon depart for Offutt Air Force Base in Nebraska.
The Pentagon announces that two aircraft carriers, the U.S.S. George Washington and the U.S.S. John F. Kennedy, along with five other war ships, are leaving the U.S. Naval Station in Norfolk, Virginia, headed for New York.
Mayor Giuliani announces that New York's subway and bus service have been partially restored. When asked how many people he thinks have been killed, Giuliani voices the grief many feel by saying, "I don't think we want to speculate about that -- more than any of us can bear."
U.S. officials say there are "good indications" that Saudi terrorist Osama bin Laden, who is suspected of coordinating the bombings of two U.S. embassies in Africa in 1998, is behind the attacks.
Number 7 World Trade Center, which sustained massive damage from the collapse of the north tower, is on fire. Everyone in the building has already been evacuated.
The New York Stock Exchange, American Stock Exchange, and Nasdaq announce they will not open on Wednesday, September 12.
President Bush returns to Washington from Offutt Air Force Base in Nebraska.
Number 7 World Trade Center collapses.
Mayor Giuliani urges New Yorkers to stay at home on the next day, Wednesday, September 12.
New York's police department announces that at least 78 of its officers are missing. The city also announces that hundreds of firefighters have been killed.
In a televised address, President Bush says, "thousands of lives were suddenly ended by evil" and asks Americans to pray for the victims and their families. The president announces the U.S. government will not differentiate between terrorists and those who harbor them.
Mayor Giuliani announces that the city does not need any more volunteers for the immediate rescue work.