Well, personally, I was in London during 9/11, which was good since scores of my friends and colleagues died in the the world trade center, including two co-workers / friends who took my place at a regular market data meeting on the 110th floor. I stayed at a hotel airport trying to fly out while all the flights were cancelled. I will always remember - the hotel airport usually flew a U.S. flag, probably because so many US travelers stayed there. But that day, they took the US flag down. Why ? I guess because they feared being a target due to flying the US flag right after 9/11. Was that the tip of the iceberg ?