Phantom Zone

The Phantom Zone
Notable Residents	General Zod, Prometheus (for a time)
First Appearance	Adventure Comics #283 (April, 1961)
Location	Another dimension
Points of Interest	Prometheus' Crooked House

The Phantom Zone is a dimension in the DC Universe where the criminals of Krypton (and generally Superman) were kept.

History

Kryptonian Use

An interdimensional realm outside of the space/time continuum, the Phantom Zone is a space that originally contained no physical material. One entity, Aethyr, had lived in the Phantom Zone for an unknown amount of time and is believed to be its only native resident. The Phantom Zone was otherwise empty until it was discovered by the Kryptionian scientist Jor-El. Afterwards Jor-El created a projector to send people into the Phantom Zone and decided that it may make an alternative form of imprisonment, believing that it might be more humane than conventional forms, as people who are within the area need neither food nor sleep. Furthermore, those imprisoned in the Phantom Zone are capable of seeing into the regular world, though are unable to interact with it in any way. This form of imprisonment eventually replaced an earlier one, in which criminals were sent into suspended animation in a capsule orbiting Krypton with special crystals being used to destroy criminal behavior within their minds. To send criminals to the into the Phantom Zone, Jor-El created the Phantom Zone Projector, a device that could send people into the Phantom Zone and retreive them with the flick of a switch. Soon, all of Kryptons most dangerous criminals were held captive in the Phantom Zone and Jor-El was responsible for putting such Kryptonian criminals Jax-Ur (a renegade scientist) and General Zod (a military insurrectionist) into the Phantom Zone.

The End of Krypton

When Jor-El later predicted that Krypton would be destroyed by a natural event, Jor-El suggested that the population could be saved by evacuating into the Phantom Zone, but such a plan was never brought to fruition. Krypton was destroyed by a natural disaster and as Jor-El predicted the Phantom Zone criminals survived due to being in another dimension. Being cut-off from their home dimension, it would be many years before the residents would learn what happened to Krypton.

Superboy

Years later, a number of Kryptonian artifacts, including a Phantom Zone projector, landed on Earth. It was discovered by Superboy, who was the last living survivor of Krypton, not including the Kryptonian prisoners. Due to an accident, however, Superboy is sent to the Phantom Zone, though finds he can, in some ways, communicate with the physical plane and is eventually capable of telling his father how to bring him back. He would later use it to send those whose sentences were complete to the bottle city of Kandor, the last remaining Kryptonian city that had been shrunk down to a tiny size. Since then, Superboy kept the Phantom Zone Projector until he grew into adulthood. Later, Superboy would meet the alien superhero Mon-El, who found himself dying due to exposure to lead, which was poisonous to his people.

Superman

Superboy eventually became Superman and in his adult life had to deal with threats from the Phantom Zone on multiple occasions. Most promenent of those were Zod and Jax-Ur, though Superman faced, over time, other notable escapees.  Superman also later on came into contact with the only surviving Kryptonian City, the City of Kandor. The city was shrunken, however, and Superman was unable to restore it to normal, so he took care of it, keeping it in his base, the Fortress of Solitude and even shrinking himself down to visit with its people. Superman then decided to release those who have finished their sentences in the Phantom Zone to be shrunk down and become free citizens of Kandor.