Guantanamo Bay is a prison located on Cuba and run by the U.S. government as part of the Guantanamo Bay Naval Base. It is often referred to as "Gitmo", from its airfield code designation GTMO.
After Kahndaq was "liberated" by A.R.G.U.S. in late 2012, Ravan Nassar was imprisoned in Guantanamo Bay in place of President Muhunnad. Over two years later, Nassar was allowed out to help the Suicide Squad fight Onslaught, but returned after refusing to re-join the team.