United Flight 175 and American Flight 11 left from Boston. American Flight 77 took off from Washington, DC, and United Flight 93 from Newark, New Jersey. That is when American Flight 11 crashed into the North Tower of the World Trade Center in New York City. After the attacksThe impacts of the planes set off intense fires that quickly spread through the World Trade Center towers, weakening the steel supports. Four new towers now rise from the site, with the tallest being the One World Trade Center.