The 102 minutes that changed America
The attacks that left nearly 3,000 people dead took less than two hours to carry out.
First, two planes smashed into New York's World Trade Center, killing 2,753.
A third plane hit the Pentagon defence headquarters in Washington, killing another 184 people.
Forty more died after a fourth plane crashed into a field in Shanksville, Pennsylvania. Investigators believe it had been headed for the White House but was stopped by a passenger revolt.
This piece drawn up by AFP for the 15th anniversary in 2016 of what became known as just 9/11 shows how events unfolded.
- 8:46 am: The first strike -
An American Airlines Boeing 767 making a Boston-Los Angeles connection with 92 people on board -- including five hijackers -- smashes into the North Tower of the World Trade Center (WTC), leaving a giant hole in the building's facade. Thick smoke trails into the sky from the tower's upper floors.
- 9:03 am: Second tower hit -
A United Airlines Boeing 767 making a Boston-Los Angeles connection with 65 people on board -- including five hijackers -- hits the South Tower of the WTC, sparking a massive explosion.
- 9:30 am: Bush speaks -
Then US president George W. Bush, in Sarasota, Florida, calls the blasts "an apparent terrorist attack". He orders "a full-scale investigation to hunt down and to find those folks who committed these acts" and says he will immediately return to Washington.
- 9:37 am: Pentagon hit -
An American Airlines Boeing 757 making a Washington Dulles-Los Angeles connection with 64 people on board -- including five hijackers -- smashes into the Pentagon in suburban Washington, setting off two explosions.
- 9:42 am: Planes grounded -
The US Federal Aviation Administration (FAA) orders the cancellation of all commercial flights in the United States.
- 9:59 am: South Tower collapses -
The WTC's South Tower, hit 56 minutes earlier, collapses in a huge cloud of smoke and dust.
- 10:03 am: Crash in Pennsylvania
A United Airlines Boeing 757 travelling from Newark to San Francisco with 44 people on board -- including four hijackers -- crashes into a field near Shanksville, Pennsylvania, after passengers and crew apparently fought with the hijackers.
- 10:28 am: North Tower collapses -
The North Tower of the WTC collapses, an hour and 42 minutes after it was struck. A huge cloud of dust blankets lower Manhattan.