A hijacked passenger jet, American Airlines Flight 11 out of Boston, Massachusetts, crashes into the north tower of the World Trade Center, tearing a gaping hole in the building and setting it afire.
A second hijacked airliner, United Airlines Flight 175 from Boston, crashes into the south tower of the World Trade Center and explodes. Both buildings are burning.
The Federal Aviation Administration shuts down all New York City area airports.
The Port Authority of New York and New Jersey orders all bridges and tunnels in the New York area closed.
President Bush, speaking in Sarasota, Florida, says the country has suffered an "apparent terrorist attack."
The FAA halts all flight operations at U.S. airports, the first time in U.S. history that air traffic nationwide has been halted.
American Airlines Flight 77 crashes into the Pentagon, sending up a huge plume of smoke. Evacuation begins immediately.
The White House evacuates.
Bush departs from Florida.
The south tower of the World Trade Center collapses, plummeting into the streets below. A massive cloud of dust and debris forms and slowly drifts away from the building.
Secret Service agents armed with automatic rifles are deployed into Lafayette Park across from the White House.
A portion of the Pentagon collapses.
United Airlines Flight 93, also hijacked, crashes in Somerset County, Pennsylvania, southeast of Pittsburgh.
The United Nations building evacuates, including 4,700 people from the headquarters building and 7,000 total from UNICEF and U.N. development programs.
In Washington, the State and Justice departments are evacuated, along with the World Bank.
The FAA reports that all inbound transatlantic aircraft flying into the United States are being diverted to Canada.
The World Trade Center`s north tower collapses from the top down, releasing a tremendous cloud of debris and smoke.
All federal office buildings in Washington are evacuated.
Police confirm the plane crash in Pennsylvania.
New York Gov. George Pataki says all state government offices are closed.
New York City Mayor Rudolph Giuliani urges New Yorkers to stay at home and orders an evacuation of the area south of Canal Street.
American Airlines reports it has lost two aircraft. American Flight 11, a Boeing 767 flying from Boston to Los Angeles, had 81 passengers and 11 crew aboard. Flight 77, a Boeing 757 en route from Washington`s Dulles International Airport to Los Angeles, had 58 passengers and six crew members aboard. Flight 11 slammed into the north tower of the World Trade Center. Flight 77 hit the Pentagon.
United Airlines reports that United Flight 93, en route from Newark, New Jersey, to San Francisco, California, has crashed in Pennsylvania. The airline also says that it is "deeply concerned" about United Flight 175.
United Airlines confirms that Flight 175, from Boston to Los Angeles, has crashed with 56 passengers and nine crew members aboard. It hit the World Trade Center`s south tower.
Los Angeles International Airport, the destination of three of the crashed airplanes, is evacuated.
The Immigration and Naturalization Service says U.S. borders with Canada and Mexico are on the highest state of alert, but no decision has been made about closing borders.
The FAA says 50 flights are in U.S. airspace, but none are reporting any problems.
Bush, speaking from Barksdale Air Force Base in Louisiana, says that all appropriate security measures are being taken, including putting the U.S. military on high alert worldwide. He asks for prayers for those killed or wounded in the attacks and says, "Make no mistake, the United States will hunt down and punish those responsible for these cowardly acts."
A state of emergency is declared by the city of Washington.
The Pentagon says five warships and two aircraft carriers will leave the U.S. Naval Station in Norfolk, Virginia, to protect the East Coast from further attack and to reduce the number of ships in port. The two carriers, the USS George Washington and the USS John F. Kennedy, are headed for the New York coast. The other ships headed to sea are frigates and guided missile destroyers capable of shooting down aircraft.
Bush leaves Barksdale Air Force Base aboard Air Force One and flies to an Air Force base in Nebraska.
The president leaves Offutt Air Force Base in Nebraska aboard Air Force One to return to Washington.
The 47-story Building 7 of the World Trade Center complex collapses. The evacuated building is damaged when the twin towers across the street collapse earlier in the day. Other nearby buildings in the area remain ablaze.
Explosions are heard in Kabul, Afghanistan, hours after terrorist attacks targeted financial and military centers in the United States. The attacks occurred at 2:30 a.m. local time. Afghanistan is believed to be where bin Laden, who U.S. officials say is possibly behind Tuesday`s deadly attacks, is located. U.S. officials say later that the United States had no involvement in the incident whatsoever. The attack is credited to the Northern Alliance, a group fighting the Taliban in the country`s ongoing civil war.
Bush arrives back at the White House aboard Marine One and is scheduled to address the nation at 8:30 p.m.
U.S. Attorney General John Ashcroft says the FBI is setting up a Web site for tips on the attacks: www.ifccfbi.gov. He also says family and friends of possible victims can leave contact information at 800-331-0075.
The New York Police Department says that at least 78 officers are missing. The city also says that as many as half of the first 400 firefighters on the scene were killed.
President Bush addresses the nation, saying "thousands of lives were suddenly ended by evil" and asks for prayers for the families and friends of Tuesday`s victims. "These acts shattered steel, but they cannot dent the steel of American resolve," he says. The president says the U.S. government will make no distinction between the terrorists who committed the acts and those who harbor them. He adds that government offices in Washington are reopening for essential personnel Tuesday night and for all workers Wednesday.