From maximum security prisons on a tiny island in the middle of the sea to cells so packed with people that disease can spread with no escape, we count 15 of the hardest and most brutal prisons in the world

Warning, text spoilers below!
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Bang Kwang Prison,
Petak Island Prison,
Kamiti Maximum Security,
Tadmor,
La Sabaneta,
Pelican Bay State,
Alcatraz Island,
Camp 1391,
Gitarama Central Prison,
Guantanamo Bay,
Carandiru,
Rikers Island,
Louisiana State Penitentiary,
Kwan-li-so No. 22,
ADX Florence Supermax Prison