My contribution just published here. It's this:

Driving to USA TODAY in Arlington, I heard the first reports. From the office, we could see smoke rising from the Pentagon. Unreal.

If you've got a memory to share of where you were or what you were thinking on Sept. 11, 2001, there's an interesting collection rapidly building on Twitter. Just mark your entry with #on911 so that others can find it.

A sampling of what's already been posted:

— glutenfreegirl: Mostly, I remember the quiet. The silence in the skies that afternoon, the way we all looked at each other, no words, understanding.

— CarFan_5801: I was woken by phone call from son telling me the towers had collapsed. I watched the TV in shock and I knew it meant war.

— yoherb: I woke up in a hotel room in LA and sat in the dark for hours watching the horror unfold. Pit in my stomach today.

— safiyama: my husband went back home for lunch money and was late for work ...as he walked to tower2, he watched his office building fall...

— j_wa: Remember gathering in the conference room to watch the news unfold. Then running home to hug my daughter. Still gives me chills.