On Sept. 11, 2001, I returned from school on an emergency early dismissal to a motionless neighborhood. It was another of many shocks when I found that my father was home early from work. I joined him in front of the living room television. In silence, we watched out-of-sequence replays of the day’s events. The rings of the Pentagon were engulfed in flames. The Twin Towers crumbled. The shattered remains of another jetliner smoldered in a Shanksville field. Smoke-plastered New Yorkers ran pell-mell through the streets as hopeless workers leaped from office buildings.

“Your world will never be the same,” my father told me.