A timeline of the attacks in the United States on Tuesday (times EDT), according to witnesses, authorities and media reports:

8:45 a.m. – American Airlines Flight 11, carrying 92 people from Boston to Los Angeles, crashes into north tower of World Trade Center.

9:03 a.m. – United Airlines Flight 175, carrying 65 people from Boston to Los Angeles, crashes into south tower of World Trade Center.

9:31 a.m. – President Bush calls the crashes an “apparent terrorist attack on our country.”

9:40 a.m. – Trading on Wall Street called off.

9:40 a.m. – American Airlines Flight 77, carrying 64 people from Washington to Los Angeles, crashes into the Pentagon.

9:48 a.m. – The Capitol and West Wing of the White House are evacuated.

9:49 a.m. – The Federal Aviation Administration bars aircraft takeoffs across the country. International flights in progress

told to land in Canada.

9:50 a.m. – One World Trade Center – the north tower – collapses.

10:29 a.m. – Two World Trade Center – the south tower – collapses.

10:37 a.m. – Officials confirm that United Airlines Flight 93, en route to San Francisco from Newark, N.J., has crashed 80 miles southeast of Pittsburgh. None of the 45 people aboard believed to have survived.

10-11:30 a.m. – Government buildings around the country are evacuated, including the Capitol and the White House. The United Nations closed down. The Securities and Exchange Commission closes all U.S. financial markets for the day. New York City Mayor Rudolph Giuliani calls for evacuation of lower Manhattan.

1:20 p.m. – Bush leaves Barksdale Air Force Base, La., for secure, undisclosed location.

2:51 p.m. – The Navy dispatches missile destroyers and other equipment to New York and Washington.

5:25 p.m. – Seven World Trade Center collapses.