Prison is far from pleasant, but things sink to an extra nasty level when prisoners are taken out of the yard and put into solitary confinement. Solitary confinement was originally a form of punishment practiced by Quakers and Calvinists who wanted to afford prisoners the quiet space to evaluate their actions, presumably while praying. Some religious sects, such as the Amish, still use forms of social isolation to punish offending members of their community, and it can wreck the psyche of those ostracized. Still, these practices don't hold a candle to the United States prison system, which takes solitary confinement to an inhumane level.