1.   It is therefore a tall but also slender building, all in brick, with a high, elegant south tower and spire.

2.   And, of course, the standing remnants of the World Trade Center, including the silvery skin of the south tower.

3.   Anthony G. Cracchiolo, a Port Authority executive, said he would have ignored the announcements made inside the south tower.

4.   As a crowd looked on, another airliner struck the south tower, exploding and setting it ablaze.

5.   As the firemen attempted to rescue people trapped in the burning buildings, the south tower collapsed on top of them.

6.   Both companies were lucky in that their offices were in the south tower, the second to be hit, and were below the impact point.

7.   Both towers partly disappeared behind thick clouds of dark smoke, then the top floors of the south tower began to fall, leaving only black smoke.

8.   Both were at the scene and were separated when the south tower collapsed.

9.   A little more than hour later, the south tower collapsed, and the north tower folowed it.

10.   A sudden bang accompanies the image of a second plane slamming into the south tower.