Eastern State Penitentiary

The most expensive public building in America was a prison designed to keep men apart.

In 1787, weeks before delegates began drafting the Constitution, a group of Philadelphians including Benjamin Franklin and Dr Benjamin Rush set out to reform how the young country punished people. What eventually came of that thinking stands in the Fairmount section of Philadelphia.

Construction started in 1822 on ten acres of elevated farmland called Cherry Hill, and the place was originally named Cherry Hill State Prison. John Haviland designed it, and it opened on 25 October 1829: seven corridors of heated, sky-lighted cells radiating from a central hub like a wagon wheel, built to hold 500 people in isolation. At completion it was the largest and most expensive public structure ever erected in the United States.

It is considered the world's first true penitentiary. Its method, refined from the Walnut Street Jail and known as the Pennsylvania system or the separate system, put reform ahead of punishment by keeping prisoners separately confined. The rules held the staff to account as well as the inmates: the warden was legally required to visit every prisoner every day, and the overseers were required to see each of them more often than that. More than 300 prisons worldwide were modelled on the design.

It ran until 1971. Al Capone was held here, and so was the bank robber Willie Sutton. James Bruno, known as Big Joe, and several male relatives were imprisoned here between 1936 and 1948 for their part in the Kelayres massacre of 1934, and were then paroled.

It is now a National Historic Landmark, open to the public as a museum with tours running daily. What you walk through is a ruin kept as a ruin, and the architecture makes the argument the founders were making: a building shaped entirely around the belief that solitude could reform a person.