1. Ohio State Reformatory, United States: For more than 100 years, this prison was considered one of the most violent in the US and several people died here.
2. Castle of San Juan de Ulúa, Mexico: San Juan de Ulúa is the name of a small Mexican island that houses a complex of fortresses, including a prison.
3. Tuol Sleng, Cambodia: More than 17,000 people were arrested, tortured, and subjected to poor conditions in this security prison.
4. Eastern State Penitentiary, United States: The prison was designed to isolate inmates, so that they could get closer to God and get rehabilitated.
5. Fremantle Prison, Australia: This imposing monument was built during the 1850s. At one point, it was used to house prisoners transported from England and Ireland.
6. Château d'If, France: 'The Count of Monte Cristo' made the prison world-famous as it tells the story of when Edmond Dantès and his mentor, Abbé Faria, were prisoners at the Château.
7. Tower of London, England: Some say the site is haunted as numerous prisoners were tortured and executed onsite, including Queen Anne Boleyn and Lady Jane Gray.
8. Alcatraz, United States: It was designed to house prisoners who were constantly causing problems in other federal prisons and became one of the most famous and feared prisons in the US.
9. Kilmainham Gaol, Ireland: The prison opened in 1796 and many of the leaders of the Irish rebellion were imprisoned and executed here.
10. Robben Island, South Africa: The prison is now a UNESCO World Heritage Site and also one of the most emblematic monuments in South Africa.