5:45 a.m.
Hijackers passed through security in Portland, Maine. A total of 19 terrorists hijacked four California-bound airplanes, from Boston, New Jersey and Washington D.C.
Photo from 9/11 Memorial Timeline
7:59 a.m.
American Airlines Flight 11 left Boston, holding 11 crew members, 76 passengers and five hijackers.
Photo from FAA
8:15 a.m.
United Airlines Flight 175 left Boston, holding nine crew members, 51 passengers and five hijackers.
Photo from 9/11 Memorial Timeline
8:19 a.m.
American Airlines flight attendent contacted Airlines ground crew alerting them of a hijacking underway on Flight 11.
Photo from 9/11 Memorial & Musem
8:24 a.m.
Mohamed Atta pressed the wrong button while trying to transmit a message to crew and passengers on board Flight 11. The message was transmitted to air traffic control which alerted them of the hijacking.
Photo from Britannica
8:37 a.m.
Air traffic control alerted the U.S. Air Force after hearing the message from Flight 11. The Air Force mobilized guard jets to identify and follow Flight 11.
Photo from ISHN.com
8:42 a.m.
American Airlines flight took off, holding seven crew members, 33 passengers and four hijackers.
Photo from Aviation24.be
8:46 a.m.
Five hijackers crashed Flight 11 into the 93 through the 99 floor of the North tower. The 76 passengers, 11 crew members and hundreds inside the building were killed.
Photo from NBC News
9 a.m.
Flight attendant, Robert John Fangman, reported hijacking of Flight 75.
Photo from Never Forget
9:03 a.m.
The five hijackers crashed Flight 175 into the 77 through 95 floors of the south tower, killing all on board along with an unknown amount inside the building. Shortly after the south tower is attacked, workers jumped or fell out of the building.
Photo from Joint Base Langley-Eustis
9:12 a.m.
The five hijackers crashed Flight 77 into the Pentagon, killing the 53 passengers and six crew members. The crash sparked a fire killing 125 civilians and military personnel.
Photo from Britannica
9:59 a.m.
The south tower fell in under 10 seconds, after burning for 56 minutes. There were more than 800 men and women, including first responders, killed in the fall of the tower.
Photo from Homeland Security Today
10:03 a.m.
Flight 93 crashed into a field in Shanksville, Pennsylvania, after passengers and crew stormed the cockpit.
Photo from the FBI
12:30 p.m.
A group of 14 survivors found in the ruins of a lower stairwell of the North Tower.
Photo from Eglin Air Force Base
5:20 p.m.
After burning for several hours, the World Trade Center fell.
Photo from 9/11 Memorial Timeline