Day before yesterday, as often happens on Wednesdays, I was a walker in the city. And because it was the first full day of shutdown (many federal employees having come in on Tuesday to sign papers before being furloughed), I strolled through an eerily quiet D.C.

I angled down New Jersey to the Capitol and walked around it to First Street, N.E. The police were in full force and I remember thinking, this is probably not a good place to be today.

But the blue sky and mild air drew me along, down the hill to the Botanical Gardens (closed), past the American Indian Museum (closed), the Air and Space (closed) and across the Mall itself. Even the grass was closed.

Finally, crossing Constitution and Pennsylvania, angling up Indiana to E Street and the courts (not yet closed), I found people again, and some of the liveliness of a typical weekday afternoon.

Yesterday, as I heard police sirens racing down Constitution from my office (on lockdown), searching for news of the shooting at the Capitol (also on lockdown) I thought about Wednesday’s route.

Twenty-four hours later and I would have been crouching behind a tree.

(Yesterday’s car chase along Constitution Avenue passed a shuttered National Archives, pictured here on a more typical afternoon.)