The September 11 Occurrence in 2001, This is What Happened.
On Tuesday 11 September 2001 suicide attackers seized US passenger jets and crashed them into two New York skyscrapers, killing thousands of people.
Gathogo Wanjiru 
The attack remains one of the most traumatic events of the century, not only for Americans but also for the world. Four planes flying over the eastern US were seized simultaneously by small teams of terrorist hijackers.
They were then used as giant, guided missiles to crash into landmark buildings in New York and Washington. Two planes struck the Twin Towers of the World Trade Center in New York.
The first hit the North Tower at 08:46 Eastern Time (13:46 GMT). The second crashed into the South Tower at 09:03.
The buildings were set on fire, trapping people on the upper floors, and wreathing the city in smoke. In less than two hours, both 110-storey towers collapsed in massive clouds of dust.
At 09:37 the third plane destroyed the western face of the Pentagon - the giant headquarters of the US military just outside the nation's capital, Washington DC.
The fourth plane crashed in a field in Pennsylvania at 10:03 after passengers fought back. It is thought the hijackers had meant to attack the Capitol Building in Washington DC.
In all, 2,977 people (not counting the 19 hijackers) lost their lives, most of them in New York, all 246 passengers, and crew aboard the four planes were killed, at the Twin Towers, 2,606 people died - then or later of injuries while Pentagon 125 people were killed
The youngest victim was two-year-old Christine Lee Hanson, who died on one of the planes with her parents Peter and Sue while the oldest was 82-year-old Robert Norton, who was on another plane with his wife Jacqueline, en route to a wedding.
An Islamist extremist network called al-Qaeda planned the attacks from Afghanistan. Led by Osama Bin Laden, al-Qaeda blamed the US and its allies for conflicts in the Muslim world.
Nineteen people carried out the hijackings, working in three teams of five and one of four. Each group included someone who had received pilot training. This was carried out at flying schools in the US itself.
Less than a month after the attacks, President George W Bush led an invasion of Afghanistan - supported by an international coalition - to eradicate al-Qaeda and hunt down Bin Laden.
However, it was not until 2011 that US troops finally located and killed Bin Laden in neighboring Pakistan.
