Prisoners in Norway, for example, don't have bars in their rooms, and have access to musical instruments, DVDs, and video games. Meanwhile, in Malawi, a typical cell is squalid and packed with dozens of prisoners.
The wide range of conditions reflects how each country treats its criminals, and raises the question of whether prison is meant to punish them or rehabilitate them.
Read on to see what prison cells look like around the world.
USA: San Quentin State Prison is the oldest prison in California. It's a maximum-security facility that once housed Charles Manson.
USA: Rikers Island in New York City was named one of America's 10 worst prisons by Mother Jones. The prison is known for inmate violence and abuse at the hands of staff.
USA: The Federal Correctional Institution in El Reno, Oklahoma, is a medium-security facility that houses about 1,000 male inmates.
CANADA: Bordeaux Prison in Montreal houses 1,000 to 1,500 male inmates with sentences of two years or less
HAITI: Civil Prison in the coastal town of Arcahaiea is notoriously overcrowded. In 2016, 174 inmates escaped during a riot that left one guard dead and others injured.
MEXICO: Penal del Altiplano is a high-security prison in Almoloya de Juárez. It was thought to be the most secure prison in Mexico until Joaquín 'El Chapo' Guzmán escaped from it in 2015.
COLOMBIA: At El Buen Pastor women's prison in Bogota, as many as 20 inmates can be assigned to a single cell.
BRAZIL: Inmates face mortal danger at Desembargador Raimundo Vidal Pessoa penitentiary in Manaus. Four people were killed in an inmate uprising last year, and dozens were killed in other prisons in the city.
GERMANY: Conditions are considerably better at Landsberg Prison in Landsberg am Lech. The progressive prison provides training and skills to inmates in fields like baking, carpentry, and painting.
NORWAY: Jails in Norway are meant to mimic outside conditions as much as possible to prepare inmates to reenter society. At Oslos' Skien prison, inmates have private bathrooms, a TV, and video games.
NETHERLANDS: Inmates at Norgerhaven prison in Veenhuizen have a bed, furniture, a refrigerator, and a TV in their cells, as well as a private bathroom. They also get a window with a view to the prison yard.
UNITED NATIONS: The UN Detention Unit outside the Hague, Netherlands, is where more than 100 war criminals are housed. Each cell contains a TV, but inmates do not get internet access.
MALAWI: Maula Prison in Lilongwe is severely overcrowded — in 2015, almost 200 people were crammed into one 60-person cell. Prisoners there, many of whom are Ethiopian migrants, share one toilet between 120 people and one tap to 900 people.
ISRAEL: Neve Tirza is Israel's only women's prison. Most cells are 13 square meters including a toilet and shower. Each cell houses about six women, who often have to share sleeping spaces.
BANGLADESH: About 1,200 inmates live in Kashimpur Central Jail in Gazipur.
RUSSIA: At the notorious Black Dolphin Prison on the Kazakhstan border, inmates share small 50-foot cells that are set back about 3 feet from the door — a 'cell within a cell.' Inmates are kept under 24-hour surveillance.
JAPAN: At Abashiri Prison in Japan, guards inspect inmates' rooms once a day. The prison houses inmates with sentences of eight years or less.
IRAN: Evin Prison in Tehran has been accused of withholding food and medical care from prisoners.