The birthplace of Supergirl, a city of the planet Krypton which survived the death of its native planet when it was hurled into outer space, people and buildings alive and intact, by the force of the cataclysm that destroyed the planet.
According to the early texts bearing on this subject, Argo City was "enclosed in a bubble of air" when the land chunk on which it was situated was hurled into space. Later texts, such as the Supergirl story in Action Comics No. 316, assert that the city was covered by an airtight plastic "weather dome" at the time of the disaster to accommodate the "atmospheric experiments" being conducted there by the scientist Zor-El.
For more than fifteen years the people of Argo City survived on their tiny island in space, until finally the entire population succumbed to Kryptonite poisoning, leaving Supergirl and her parents—Zor-El and Alura—the only survivors.
Most of what is known concerning the fate of Argo City and its people is first told in the Supergirl story in Action Comics No. 252. When the planet Krypton exploded into fragments and Argo City was cast into space, explains this text, the survivors had high hopes of survival, since they had more than sufficient air to breathe and a "food machine" to provide them with nourishment. Their optimism was short-lived, however, for they soon discovered that the ground beneath them had begun to radiate a greenish glow. This was due to the fact that the atomic chain reaction that destroyed Krypton had converted their shattered planet into kryptonite (later chronicles state "Anti-Kryptonite"), an element whose radiations were capable of poisoning and destroying them.
Zor-El resolves the potentially fatal dilemma by covering the ground with sheet lead, thereby effectively shielding the deadly kryptonite radiations threatening the lives of the Argo City survivors.
For years Argo City drifts through space as life returns to an uneasy normalcy for its small but hardy population. Zor-El takes a wife, named Alura, and in time a blond baby girl, Kara, is born to the couple. But a cruel fate is in store for the people of Argo City. For one day, after Zor-El's daughter has become a teen-ager, a swarm of meteors strike the city, smashing gaping holes in Zor-El's kryptonite-proof lead shield and releasing the deadly kryptonite radiation into the air.
Within about a month virtually the entire population has succumbed to kryptonite poisoning, but not before Zor-El has placed his teen-aged daughter inside a small rocket ship and launched her toward Earth, where she will acquire super-powers identical to Superman's and achieve worldwide renown as Supergirl.
For some time, it is believed that Zor-El and Alura have perished along with the rest of Argo City, but it ultimately develops that the renowned scientist and his wife have survived the death of their city by escaping into the so-called Survival Zone, an alien dimension which Zor-El himself had discovered. Supergirl frees her parents from the Survival Zone in 1964. Zor-El and Alura now reside in Kandor. (TGSB)