At work when I heard about the first plane on the radio. Flipped on the TV and the co-workers gathered. Watching the second plane approach was the most difficult - we all knew what was going to happen, but were powerless to do anything.
I live near a small commuter airport w/ flight school and we're used to the planes buzzing overhead. With the no-fly aftermath, there was an eerie silence that only added to the gloom.
I'm grateful that we haven't had any more - unlike some other countries that still have to deal with that menace. Violence as a result of political disagreements, I can somewhat understand. It disgusts me that all that carnage was, and is still being done, in the name of religion (man). I can't accept that any true God could condone these actions taken in His name.