I called in sick to work the morning of Sept. 11, 2001. I had the remnants of a flu bug that had popped up over the weekend and, rather than drive the 30 miles to America Online and possibly infect my co-workers, I decided to rest up one more day.

I flipped on the ‘Today’ show on television and NBC was broadcasting pictures of a burning World Trade Center. Matt Lauer, I think, said he wasn’t sure yet what had happened, but that it appeared a private plane had crashed into one of the towers. How wrong he was.

The thing I remember most about that morning is watching the first tower fall. My brain couldn’t process what my eyes were seeing. “I couldn’t believe it was happening” is a terribly overworked phrase, but in this case it was quite literally true. This sort of horror was not imaginable, but it turned out to be only one of a series of unimaginable horrors of that day.

Also not imaginable before that day was America’s response. I have never been prouder to be an American than I was in the days after 9/11. All of the petty bullshit that dominates modern American politics was swept away and there was a sense that we were all in this together. And most of the world genuinely grieved with us.

Five years later, that all seems remarkably quaint.