The Eastern State Penitentiary (ESP) is a former American prison in Philadelphia, Pennsylvania. It is located on 2027 Fairmount Avenue between Corinthian Avenue and North 22nd Street in the Fairmount section of Philadelphia and was operational from 1829 until 1971. The penitentiary refined the revolutionary system of separate incarceration first pioneered at the Walnut Street Jail which emphasized principles of reform rather than punishment. Notorious criminals such as bank robber Willie Sutton and Al Capone were held inside its unique wagon wheel design. When the building was erected it was the largest and most expensive public structure ever constructed, quickly becoming a model for more than 300 prisons worldwide.