Behind Bars: The World's Toughest Prisons

Tent City Jail sleeping in old army tents and working in chain gangs under the burning Arizona Desert Sun.

Originally built for 800 prisoners, Antanimora Prison in Antananarivo, Madagascar, houses over 3,000. Disease and rats rule here as prisoners sleep body against body, and malnutrition is said to be one of the main causes of death.

Inmates rule and anarchy prevails at San Pedro Prison in La Paz, Bolivia. Only the strongest survive in the lawless prison city, where prisoners disappear without a trace and guards never enter because they fear for their lives.

The Dallas County Jail in Texas has room for 7,100 inmates, from small-time criminals to serial killers waiting for their day in court. Those who enter must be aware of the relentless turf battles and gang warfare.

Sofia Central Prison in Bulgaria is a dilapidated detention center fit for demolition. In addition to inmates living in less than half the required square footage, inter-prisoner violence is rampant and abuse by guards is rumored.

Miami-Dade County Jail and Boot Camp is two worlds in one prison complex. A protocol is used to break the inmates by boot camp drills in one, and murderers, rapists and robbers adhere to their own rules to survive in the other.