I was at work in downtown Houston in the tallest building in the city. I worked for Morgan Stanley at the time. We turned on the TV after the first plane hit, just in time to see the second plane hit.
After that occurred, we were told by management to evacuate the building. I drove home and spent the day with my one year old son and wife, watching TV and crying.
Morgan Stanley had thousands of employees in the WTC, most of whom made it out alive because of the the actions of the on site security manager,
Rick Rescorla, who had been an Army officer during the Vietnam war and had made contingency plans for the WTC after the 1993 bombing. Even as WTC building management was telling employees to stay put, Rescorla was evacuating Morgan Stanley employees.
Rescorla died at the WTC that day, but his actions that day and his preparations beforehand saved probably thousands of lives.