8:46 a.m. ET : Hijackers crash Flight 11 into the north tower.
9:03 a.m: Hijackers crash United Airlines Flight 175 into the south tower.
9:37 a.m: Hijackers crash American Airlines Flight 77 into the Pentagon.
9:59 a.m: The south tower collapses.
10:03 a.m: Passengers launch a counterattack on hijackers aboard United Airlines Flight 93. The hijackers crash the plane into an empty field near Shanksville, Pa.
10:28 a.m: The north tower collapses.