It is difficult to watch knowing the terror which my brother must have endured on the 105th floor of the North Tower. I cannot imagine the thoughts which he must have had as the entire floor was engulfed in smoke and flames. He must have realized that the tower would collapse because the South tower fell first (even though it was struck second).
It is believed that my brother was one of the many 'jumpers' who would rather have their remains found (as his was) than to be incinerated in the falling buildings holocaust of heat. Virtually none of his co-workers were found and their families had nothing to bury.
I remember when we were young and visited the Empire state building my brother was not afraid of heights. I developed a somewhat mild case of fear of heights, and would not go near the edge of the 86th floor observation deck.