7:58 a.m.

United Airlines Flight 175 departs Boston for Los Angeles, carrying 56 passengers, two pilots, and seven flight attendants. The Boeing 767 is hijacked after takeoff and diverted to New York.

7:59 a.m.

American Airlines Flight 11 departs Boston for Los Angeles, carrying 81 passengers, two pilots, and nine flight attendants. This Boeing 767 is also hijacked and diverted to New York.

8:01 a.m.

United Airlines Flight 93, a Boeing 757 carrying 38 passengers, two pilots, and five flight attendants, leaves Newark, N.J., for San Francisco.

8:10 a.m.

American Airlines Flight 77 departs Washington's Dulles International Airport for Los Angeles, carrying 58 passengers, two pilots, and four flight attendants. The Boeing 757 is hijacked after takeoff.

8:46 a.m.

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 on fire.

9:03 a.m.

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.

9:10 a.m.

In Florida, President Bush is reading to children in a classroom when his chief of staff, Andrew Card, whispers news of the attacks into his ear.

9:18 a.m.

U.S. Federal Aviation Administration shuts down all New York area airports.

9:21 a.m.

Bridges and tunnels leading into New York City are closed.

9:25 a.m.

All domestic flights are grounded by U.S. Federal Aviation Administration.

9:30 a.m.

First remarks by the President After Two Planes Crash Into World Trade Center given from Emma Booker Elementary School in Sarasota, Florida. He then leaves to board Air Force One.    Hear Remarks

9:43 a.m.

American Airlines Flight 77 crashes into the Pentagon, sending up a huge plume of smoke. Evacuation begins immediately.

10:05 a.m.

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.

10:05 a.m.

The White House is evacuated.

10:10 a.m.

A large portion of one side of the Pentagon collapses.

10:10 a.m.

United Airlines Flight 93, also hijacked, crashes in Somerset County, Pennsylvania, southeast of Pittsburgh.

10:24 a.m.

The FAA reports that all inbound transatlantic aircraft flying into the United States are being diverted to Canada.

10:28 a.m.

The World Trade Center's north tower collapses from the top down as if it were being peeled apart, releasing a tremendous cloud of debris and smoke.

11:18 a.m.

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.

11:26 a.m.

United Airlines reports that United Flight 93, en route from Newark, New Jersey, to San Francisco, California, has crashed in Pennsylvania.

11:59 a.m.

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.

1:04 p.m.

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."

1:48 p.m.

President Bush leaves Barksdale Air Force Base in Louisiana aboard Air Force One and flies to an undisclosed location.

4:30 p.m.

Bush leaves Offutt Air Force Base aboard Air Force One to return to Washington, where he will make a nationally televised address.

5:20 p.m.

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.

7:45 p.m.

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.

8:30 p.m.

Bush addresses the nation. "These acts of mass murder were intended to frighten our nation into chaos and retreat," he said. "But they have failed; our country is strong."     Hear Statement

8:35 p.m.

Bush attends national security meeting.