The North Tower of the WTC collapses after burning for 102 minutes, killing approximately 1,400 in the building and surrounding area.1

1 “North Tower Collapses” National September 11 Memorial and Museum n.d. Web. March 17, 2011 http://timeline.national911memorial.org/#/Explore/2/Entry/57/81
Courtesy of the National 9/11 Memorial and Museum