September 11 on TV

I'm always glad the National Geographic Channel and the History Channel air the September 11 documentaries every year. It's important to remind yourself of the true horror of that day.  The image that's always been the most traumatic for me is the sight of Flight 175 slicing into the South Tower. Because we never actually saw the other 3 attacks, this one is the most vivid memory;seeing that, and seeing the size of the plane and the tower, you realize how terrified the passengers on all the planes must have been that day -- and how brave.