I was in London at the time, two weeks into a three-month work visa. My co-workers and I heard about the first plane on the radio, and I remember thinking that the pilot must have been drunk, because how else could someone hit a building that big? It didn't occur to any of us at the time that it was deliberate. A bit later we heard about the second plane and knew it was something very different. We watched the towers fall on television, and then closed up shop and headed home because there was talk of the Tube possibly being closed. When I exited the Tube station at Tottenham Court Rd., the evening papers already carried the headlines, only about four hours after the first plane hit. Someone must have literally stopped the presses.
I lived in a hostel with about 20 others, people from the U.S. and Canada and other places, including a lady from Afghanistan. We collectively spent the next two days in front of the TV, and tensions were a bit high. The first night a few of the Americans went to Heathrow to try to catch a flight home, but they soon returned because there were no flights to America. Around the same time a new arrival showed up - he had flown out of JFK about 8am NYC time, and had no idea what was going on.
There was a memorial at St. Paul's on Friday. I went but despite arriving several hours early, the cathedral was full. I stood outside with thousands of other people of all nationalities, and we listed to the service on loudspeakers. It was a beautiful day and American flags were flying all around the block. We sang "Battle Hymn of the Republic", and that was when I finally lost it. I cried for hours. Later there was a city-wide three minutes of silence, and I swear it seemed like everyone, every car, every bus, everything was completely still. I have never heard London so silent.
The thing I remember most was how sympathetic all the people I met were. As soon as people realized I was American (as soon as I spoke!), they said how sorry they were. There were American flags in shops windows and bus windows. And Tony Blair said "we support our American cousins" and "we will not rest until we eradicate this evil from our world". I really had no concept of what that meant, but at the time it was a great comfort and I fell a little bit in love with him.
