1. Tuol Sleng, Cambodia:
This prison is an infamous prison situated in Cambodia. This prison was opened by the brutal Khmer Rouge in 1975 this was a high school converted to a prison. It was open only for four years. Of the 18000 who had been inmates, only seven were saved in 1979 when the Vietnamese army liberated the prison. Tuol Sleng became a museum soon after its closure as a prison. It acts as a memorial to all those killed during the Khmer Rouge regime which ruled Cambodia. The museum is just outside Phnom Penh and is open daily.
2. Hanoi Hilton (Hoa Loa Prison):
This prison in Vietnam, is nestled somewhat oddly at the foot of an imposing high-rise in the city centre. This prison was built by the French to house Vietnamese political prisoners. According to the reports of the prisoners, Vietnamese jailers used torture, starvation, and murder to subdue them. Some of the most notable figures that spent time in that prison were US Senator John McCain, future U.S. Vice-Presidential candidate James Stockdale and decorated U.S. Air Force pilot Bud Day. Today, this prison serves as a hotel under the name Hilton Hanoi Opera Hotel.
3. Elmina Castle in Ghana
Built in 1492, represents one oldest European building that still stands south of Sahara. For over three hundred years, this prison was served as a holding area for people captured against their will and sold into slavery. The conditions were dismaying where each cell held almost 200 people with no space even to lie down. By the 18th century, over 30,000 slaves were passing through the door of no return each year. Elmina castle reached worldwide fame when president Obama visited in 2009. It is now a UNESCO world heritage site and open for tourists.
4. Port Arthur, Tasmania
Port Arthur located in Tasmania, Australia, was once a penal colony. It is now a UNESCO World Heritage Site. It operated from 1833 to 1850 and housed the most dangerous criminals. It was the destination for the hardest of convicted British and Irish criminals and rebellious inmates from other prisons. The prison was located on a peninsula surrounded by rough seas. The location of the prison made it impossible for the prisoners to escape. With just a narrow strip of land known as Eagle hawk Neck connecting to the mainland was patrolled by vicious dogs. Currently this prison serves as an open museum and tourist destination.