Just about 10 years ago, I was home with my son, and I turned on the TV for the morning news. For the next hour, I would alternately break into sobs and then force smiles for the boy, as he would look confused and then cry reflexively in response. I made myself turn it off to avoid scaring him to death, but I kept checking the news online, and tried to fill in friends who were stuck at work with fewer ways to find out what was going on.
I've had many awful, awful days since then for me personally, but that was easily the worst day of my life even though I knew no one directly affected.
Here I am now, 10 years on, with another infant son whose birth could not have then been predicted. How that day will ultimately prove to have changed the world my sons will inherit is similarly unpredictable.
Where were you? What was it like? Does it matter now?
People still talk about how beautiful the sky was.