I saw the footage as part of an exercise imagining that it was the first time I had seen it, and tried to write simply what I saw. This is what I wrote:
A plane has just crashed into the second of the twin towers and a huge fireball has taken over the top floors. All you can see is a plume of dark grey smoke rising from the top, and a large hole in the side of the building.
There are people hanging out of the windows in the topmost floors and on the ground, everyone is trying to get away from the falling debris. There is smoke and dust everywhere and the firefighters are on site trying to combat the massive flames consuming the building.
One of the towers has just collapsed! All you can see now is a large cloud of dust and smoke covering the surrounding buildings from sight and billowing out.
The dust has completely covered the camera, obscuring the view. Once it settles you can see that those that have been caught inside the cloud, the cars and the road are thickly covered in ash, or dust.
All you can hear are sirens as police, ambulances and fire engines rush to the scene, while the streets are devoid of the normal hustle and bustle.
Although this post is different from what will be my normal topic, I felt that it was worth including...the sight of the Towers collapsing again, and watching the start of our war on terrorism.