In its analysis of the expansion of the prison institution since the mid 1970s, this paper chiefly examines rising inmate populations in the United States and discusses reasons why the current approach to fighting crime has been maintained in spite of its low rate of success. Drawing on the research done by Norwegian criminologist Thomas Matthiessen, it opens with a brief history of penal institutions in Europe and describes how prisons have always been geared towards disciplining the "dangerous classes," or the most marginal people in society. The principle theories that justify the existence of prisons are accepted as dominant paradigms, yet they appear more problematic when we look at empirical evidence that undermines their basis. The extent of prison expansion in the U.S. is quantified using various charts and graphs that show how fast the prison population has grown, how black Americans are about eight times as likely as whites to spend time in prison, and the role of mandatory minimum sentencing laws. The aggregate share of national income among the least wealthiest fifth of all families has also decreased since the early 1980s, which I argue is important for understanding the spike in incarceration. In the section that deals with the Danish criminal justice system, we find how murder rates in Denmark are vastly lower than in the U.S. and recidivism is significantly lower. The Danes incarcerate less than one tenth the proportion of their population that Americans do, give shorter sentences, very few life sentences, and allow inmates to go on frequent leaves, even in their maximum security prisons.