I was sitting in a chair on the ground floor of the South Tower when the attacks happened. Suddenly there was an almighty bang, like the dropping from high up of a skip full of concrete. That clang still resonates today. At the time, the event seemed unreal. It was like a film set. The blue brightness of the day heightened the unreality. My memories now are of the dignity of New Yorkers and their quiet outrage that a bunch of unelected men should dare to try to kill us, in our variety and innocence, to further their medieval views. It hardened my own politics, making me much less tolerant of a chattering-class view in Europe that "America had it coming".
I remember sitting in a car on the day with a Chinese American and listening to the radio as we drove away from Ground Zero. She was trying to get to a maternity hospital, her thoughts flitting between the big event in her body and the big event we were fleeing.
And I remember a Muslim I met who had escaped from the South Tower. She told me later that the attacks had made her think hard about her beliefs. She concluded that the faith of the attackers was a perversion, and that her own faith was true and strong.