Life has few certainties, but I'd be willing to bet my existence that every single person reading this issue of NU remembers exactly where he or she was on Sept. 11, 2001. It's a day whose events have been seared indelibly into all our memories.

I lived then and still do a little less than two miles due north of the World Trade Center. The towers were an easy landmark for directions ("when you leave the subway, head for the WTC") and close enough that I felt I could reach out and touch them from my roof. They seemed to watch over my neighborhood like benevolent giants.

As it happens, I was in San Francisco on business on the day of the attacks. As I watched the towers fall on television, I heard a sound escaping from me that is best described by the great old Irish word "keening"—a sharp, piercing wail. And I discovered that what I had seen in movies, but had never really believed, was true—a brutal emotional shock actually can make you retch.