North tower collapsing
That particular act of terrorism did not take place in my country or not even on my continent but it was exceptional in its scale. I was at a gym in Tampere where I lived at the time. It was afternoon where I live (GMT+3, NYC is in GMT-4). There were TVs on at the gym. Someone pointed at the television and told me something really bad was taking place. All we could do was watch the news riveted to where we were standing. Victims RIP.