The Eastern State Penitentiary, also known as ESP is a former American prison in Philadelphia, Pennsylvania. It is found at 2027 Fairmount Avenue between Corinthian Avenue and North 22nd Street in the Fairmount section of the city, 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 innovative wagon wheel design. At its completion, the building was the largest and most expensive public structure ever erected, and quickly became a model for more than 300 prisons worldwide.