my gf and i were in alexandria, va at the time, and she took the metro to grad school. she was at the stop under the pentagon when it got hit. her dad called and asked if we were all right -- i hadn't heard about the pentagon attack yet, so i told him we were fine -- he knew we weren't in nyc. he said to turn on the tv (i'd just gotten home from dropping her off at the metro), and i saw the reports about the wtc and the pentagon. somehow she managed to get through to me on the phones, and i had to drive into dc to pick her up. i took rt. 5 (right past the pentagon) to go get her, but it was all blocked off. it took me three hours to get to her school (15 miles from our house), and i had to go through virginia and maryland to do it.
my gf said that when they stopped at the pentagon stop, all these people came running onto the train, screaming that there was a bomb. nobody knew exactly what was happening yet.
the huge black cloud hanging over the pentagon was so odd -- all these buildings and cityscape, and a giant black cloud hanging over everything. so scary. and it was super eerie the next few days with no planes flying over, especially as we were near bwi, dulles, and ronald reagan airports. it felt like the whole world had just stopped.