Owner: Martian Manhunter (J'onn J'onzz)
Designation: Headquarters/Observation Post/Laboratory
Affiliation: White Martians
First Appearance: JLA #1 (January, 1997)
Z'onn Z'orr is an ancient Martian stronghold originally erected in secret by the White Martians on Earth in what would become known as "Antarctica". The stronghold was used as a secret facility where the martians conducted experiments on the planet's primitive human populace before their actions were discovered.
Abandoned following the war between the White and Green martians, centuries later the compound was restored and used as the base of operations for a band of White Martians known as the Hyperclan. After a fight involving the JLA, the Hyperclan were defeated and the Martian Mahunter (J'onn J'onzz) converted the site into his own private fortress.
However, Z'onn Z'orr was soon being used by J'onn's brother, Ma'alefa'ak J'onzz, to imprison and subsequently torture the Saturnian known as Jemm (whom J'onn had invited to live in the stronghold to heal) while posing as J'onn.
When Ma'alefa'ak's schemes were finally discovered, J'onn trapped himself and his brother within the stronghold and launched it into the sun in a bid to finally end his brother's evil. However, while Ma'alefa'ak and the stronghold perished, J'onn was saved by the JLA.