HOW THE TWIN TOWERS COLLAPSED
1. 08:46 - American Airlines Flight 11 to Los Angeles crashes into the North Tower 47 minutes after taking off from Boston.
2. 09:03 - United Airlines Flight 175, also heading for LA, hits the South Tower 49 minutes after leaving Boston.
3. 09:59 - South Tower collapses in 10 seconds, killing all those still inside and many nearby, including some who had fled the North Tower.
4. 10:28 - The North Tower collapses, killing occupants and rescuers.
5. An official report says the steel structures were strong enough to withstand the impacts, and would not have collapsed if the fire-resistant insulation had not been so widely dislodged, enabling the intense heat to weaken the steel supports.
6. The other buildings on the World Trade Center complex are also damaged, destroyed or demolished in the aftermath. Other neighbouring buildings suffer major damage. The complex is later razed to the ground and a new development will emerge at what has become known as Ground Zero.