 Complete the following phrase:  These plans for improvement were never realized. On the morning of September 11, 2001, Al-Qaeda-affiliated hijackers flew two Boeing 767 jets into the Twin Towers in a coordinated act of terrorism. At 8:46 a.m. Eastern Time ET, a team of five hijackers intentionally crashed American Airlines Flight 11 into the northern facade of the North Tower. At 9:03 a.m. ET, a second team of five hijackers intentionally crashed United Airlines Flight 175 into the southern facade of the South Tower. After burning for 56 minutes, the South Tower collapsed at 9:59 a.m. At 10:28 a.m., the North Tower collapsed, after burning for 102 minutes. The attacks on the World Trade Center killed 2,753 people. The resulting 