I was on my way to Houston Bush Intercontinental Airport to work on cellular communications equipment that was located on the roof of the international terminal. The first plane hit just before we got to the loading dock to check in at the security check point. On of my crew members got out of the truck and told me the first tower had been hit. We checked in and they had it on the TV monitor at the check in. I called back to the office and asked if they still wanted us working. They told us to go ahead and start but if the airport started locking down to leave. We had a little radio we took on the roof with us and we listened as we started getting set up to work. When they gave the order to ground all flights I started to worry. It was crazy. I remember watching every plane come in for a landing and wondering if it was going to crash into the building. This airport is normally very busy but on that day the sky was full of planes circling waiting for their turn to land. With the threat of another crash it reminded me of one of those pictures you see looking up from the ocean floor and all the silhouettes of the sharks circling above. Any one of those shadows could attack at any second. Then the second plane hit. At that point I called the office and TOLD them we were leaving. We got out without any incident but it was such a numbing shocking feeling. I felt as if I had been stunned by a ****** punch all day. All I could do was watch and pray for those who lost and were losing their lives. We will never forget.