Eastern State Penitentiary
Designed by John Haviland and opened on October 25, 1829, Eastern State is considered to be the world's first true penitentiary. Eastern State's revolutionary system of incarceration, dubbed the "Pennsylvania system" or separate system, encouraged separate confinement (the warden was legally required to visit every inmate every day, and the overseers were mandated to see each inmate three times a day) as a form of rehabilitation.
The Pennsylvania System was opposed contemporaneously by the Auburn system (also known as the New York system), which held that prisoners should be forced to work together in silence, and could be subjected to physical punishment (Sing Sing prison was an example of the Auburn system). Although the Auburn system was favored in the United States, Eastern State's radial floor plan and system of solitary confinement was the model for over 300 prisons worldwide.