I was at work at 1730 Pennsylvania Avenue.
As you can imagine from my location, it was not only hectic but very frightening. Made moreso by the fact that my brother works in the Senate where apparently one of the planes may have been headed. Never seen so many uniformed Secret Service in my life, and certainly never seen them carrying MP5s or whatever their machine guns were so openly. They set up snipers and some type of missile launcher/stinger(?) bunkers on the corners of the Old and New Executive office buildings at 17th+Penn as well as on the White House. I took some pictures the next day because it was the most freakish thing I had ever seen. Walked home that day, probably about a 3 hour walk, because no one wanted to take the Metro. Pray I never have to go through anything like that again.
Its funny though people ask me if I'm afraid to come to work right next to the White House. I figure, not really, if anything so catastrophic happens, like a nuke, I'm not going to feel a thing, so not going to let these pricks scare me out of making a good living.