At 8:45am, on a clear Tuesday morning, an American Airlines Boeing 767, filled with 20,000 gallons of jet fuel, was crashed into the 80th floor of the 110 floor North Tower of the World Trade Center, New York City. It appeared at that moment to be a freak accident.

The incident was broadcast live around the world.

18 minutes later, a United Airlines Boeing 767 was crashed into the 60th floor of the South Tower.

Four jets in total had been taken over by Islamic extremists under the command of Saudi Arabian fugitive Osama bin Laden, head of al Qaeda. All of the planes the extremists had chosen to hijack were bound for California so that they were heavily laden with jet fuel.

The 19 hijackers had managed to board the jets armed with box-cutters and knives. A number of them had been trained to fly at an American flight school.

At 9:45 American Airlines flight 77 slammed down into the Pentagon. 125 were killed in the Pentagon, all of the 64 people on the plane died.

Heroic passengers (who had been told what was going on in New York and the Pentagon) on the fourth plane, United Flight 93, took control of the situation and managed to crash the plane before it could be used to do more damage. One of those heroes, Thomas Burnett, Jr, cell phoned his wife to say:

"I know we're all going to die. There's three of us who are going to do something about it. I love you, honey."

That plane was brought down in an empty field in Pennsylvania at 10:10 a.m. 43 people died on the plane.

In all, around 4,000 people died in the World Trade Center and its vicinity, including 343 firefighters and paramedics, 23 New York City police officers, and 37 Port Authority police officers.

In a television address at 7pm on this night, President George W Bush told the nation:

"Terrorist attacks can shake the foundations of our biggest buildings, but they cannot touch the foundation of America. These acts shatter steel, but they cannot dent the steel of American resolve."