At the time, I was working at Sprint's internal help desk, which was pretty large at the time. Once word of the first tower strike got out everyone started streaming CNN, and the Internet connection choked in short order.
So a lot of us went to the auditorium to watch TV on the big screen. Shortly after that the towers collapsed. Everyone was walking around in disbelief.
What was typically a bustling business atmosphere, suddenly came to a screeching halt. I remember the various emotions I saw expressed that day. Shock, confusion, grief and then anger.