Okay kiddo, you know how when someone does something really bad, like hurting other people or stealing, they have to go to jail? Well, the Guantanamo Bay Detention Camp is a type of jail, too, but it's a special kind of jail meant for people who are accused of doing something really, really bad - like being involved with terrorism or trying to hurt people on purpose.
The Guantanamo Bay Detention Camp is located in a place called Guantanamo Bay, which is a small area in Cuba. The jail often gets shortened to "Gitmo" for short. It's a place where people from all over the world are taken and held without being charged with a crime. They are kept there because the government believes they are a threat to the safety of the United States.
Now, most jails have specific rules they have to follow to make sure the people inside are treated fairly, but the rules for Guantanamo Bay are different. People being held there don't get trials like they would if they were in a normal prison. This means that they don't get a chance to prove that they are innocent or guilty in front of a judge or a jury like people normally do.
There's also been some controversy around the treatment of the people who are being held there. Some people are really upset that the people at Guantanamo Bay aren't being treated very well. They say that the people there are being treated unfairly, and that they should either be charged with a crime or set free.
So, in summary, Guantanamo Bay Detention Camp is a jail in Cuba where people who are accused of being involved in terrorism are held without being charged with a crime. It's controversial because people are concerned about the treatment of the people who are being held there and the lack of a fair trial.