I’ve visited Philadelphia several times over the last few years, and when I first saw the Eastern State Penitentiary, I was immediately drawn to its imposing walls. On each visit, either because of weather or my schedule, I wasn’t able to venture in.

On a visit to Philadelphia last October, I told myself that I just had to visit. Of course, it was damp that morning, and I thought I would once again fail to go. Just as the gates opened for the day, however, the weather improved!

Operational from 1829 to 1971, the initial design focused on solitary confinement—meant as form of reform based around a monk like notion of penance. With expansion and overcrowding, this system broke down, and eventually was abandoned.

Today, its cells and corridors are haunting.

"A Summer Memory": The snow is falling in Boston, but I've dug up some photos from last summer I had never processed. The Dry Tortugas National Park is one of America's more remote national parks, some 60 miles west of Key West and accessible by ferry or seaplane. Departing Key West, we quickly leave all civilization behind. The water is clear and shallow, exposing undersea highways.

As the main island of the park comes into view, the imposing brick walls of Fort Jefferson rise from the waters. Arriving before the ferry, I have time to explore this quiet, abandoned place that served as both a fort and a prison in the 19th Century.