10:45 a.m.: All federal office buildings in Washington D. C. are evacuated.

10:32 a.m.: Cheney called Bush on Air Force One to say they had just received a threat against the plane

10:28:31 a.m.: The North Tower of the World Trade Center collapses

10:10 a.m.: The FAA orders all planes to land at nearest airports.

10:06:05 a.m.: According to seismic data, United Airlines Flight 93 crashes near Shanksville, Pennsylvania, in Somerset county

9:59:04 a.m.: The south tower of the World Trade Center collapses, plummeting into the streets below

9:47 a.m.: Commanders worldwide ordered to raise threat alert status four notches to "Delta", the highest level, to defend United States.