I found Peggy Noonan’s piece for the Wall Street Journal very moving. She says something at the beginning which is obvious as soon as it is drawn to your attention, but which you might otherwise not notice.

New York saw the buildings come down.

That was the thing. It’s not that the towers were hit—we could have taken that. It’s not the fire, we could have taken that too. They bombed the World Trade Center in 1993 and took out five floors, and the next day we were back in business.

It’s that the buildings came down, in front of our eyes. They were there and proud and strong, they were massive, two pillars at the end of the island. And then they groaned to the ground and there was a cloud and when people could finally see they looked back and the buildings weren’t there breaking through the clouds anymore. The buildings were a cloud. The buildings were gone and that was too much to bear because they couldn’t be gone, they couldn’t have fallen. Because no one could knock down those buildings.

Yes, I thought, that was it. That was the stunning incomprehensible part. I was in London that day. Colleagues called me in to watch the news on TV after the first plane hit. At that point it was an inexplicable accident. Then we watched as the second plane hit, and the meaning became clear. Yet it was possible, just, to take in even that. Watching the first tower fall, with all those people still inside, simply shut me down. I had no reaction. “It’s not there,” somebody said. It was paralyzing.