Stateville Prison opened in 1925 with the capacity to house 1,506 inmates. Originally designed by criminologist Jeremy Bentham as a panopticon cell house, the structure was commonly known as a "roundhouse" that featured an armed tower in the center of an open area surrounded by cells. Pictured here in 1992, Stateville has the only remaining "roundhouse" still in use in the United States.

Photographer: Lloyd DeGrane
Source: Chicago Historical Society (ICHi-24705)