A place in Cuba where the US hold mainly Muslim and Arabic prisoners in violation of
international law.
The main camp there is known as Camp X-Ray for reasons known only to the sadists who operate the place but the clear implication being that highly unusual practices are involved.
Often Abrreviated to
Gitmo it is to the US what the concentration camps were to the Nazis and the Gulags to the Soviet Communists.
Concentration camps and Gulags were often in locations outside the motherland/
fatherland as is the case with Guantanamo Bay which is in an occupied part of Cuba nominally leased from the Cuban government who refuse to accept the US presence there but are too weak to do anything about it.