This hulking former penitentiary was once considered a progressive alternative to the much more violent and abusive prisons of the era. Inmates here spent long stretches of time alone in their cells in an attempt to inspire penitence, hence the term. Today you can visit the cell blocks, including that of their most famous involuntarily resident, Al Capone. The audio tour will lead you through the various buildings that made up the institution and there are a number of interesting history exhibits and art displays. If you are visiting between late September and early November, you can spend an evening having the bejesus scared out of you when parts of the pen are turned into a popular haunted house attraction.