Cube

The Cube was originally a S.H.I.E.L.D. black facility, one of nine classified bases. The Cube was a prison for alien criminals who committed crimes on Earth. It was here that the "Marvel Boy" was imprisoned after his brief assault on the US government. He boasted that he would make it the capital of a new Kree empire, a threat he later made good on after the superhuman Civil War.^[2] During this conflict, the sadistic warden approached S.H.I.E.L.D. to use Marvel Boy, brainwashed by his experiments, as an efficient asset against the children of the Pride. Due to interference of the Young Avengers, Marvel Boy did indeed take control of the facility.^[3]

Marvel Boy used his advanced technology to begin rehabilitating the alien inmates, but the Skrull Virus that attacked all Stark Tech equipment during their invasion destroyed his efforts. This allowed all the inmates to escape.^[4] In the aftermath of the Skrull invasion, Norman Osborn used the Cube as a base for his Thunderbolts.^[5]

Years later, the Cube had become a generalized correctional facility for superhuman criminals. Tony Stark lobbied for turning it into a more human environment for its inmates, doing away with power-dampening collars or sedated convicts.^[6] This was allegedly made possible thanks to the guards being powerful beings, able to confront Avengers-level threats.^[7]

The Cube is located somewhere in North America, though outside of the United States of America,^[10] and halfway between Los Angeles and New York City.^[11]
The Cube holds weekly "Workout Wednesdays,"^[6] and seemingly, mentioned as a joke by Iron Man, "Taco Tuesdays."^[7]