Krypton is also the native world of Supergirl, Krypto the Superdog, and Power Girl (in her case, an alternate-universe version designated "Krypton-Two"). It has been consistently described as having been destroyed shortly after Superman's flight from the planet, although the exact details of its destruction vary by time period and writers. Kryptonians were the dominant species on Krypton.
Krypton is usually portrayed in comics as the home of a fantastically advanced civilization, which tragically is destroyed when the planet explodes. As originally depicted, all the civilizations and races of Krypton perished in the explosion, with one exception: the baby Kal-El who was placed in an escape rocket by his father, Jor-El, and sent to the planet Earth, where he grew up to become Superman.
In some versions of the story, additional survivors were later discovered, such as Krypto the Superdog, Supergirl, her parents (kept alive in the "Survival Zone", a similar parallel "dimension" to the Phantom Zone), the criminal inhabitants of the Phantom Zone, Dev-Em, Beppo the Super-Monkey, the residents of the bottled city of Kandor, and the real parents of both Superman and Supergirl. Kandor, the former capital of Krypton, is miniaturized by Braniac, but it is eventually recovered by Superman and subsequently housed in the Fortress of Solitude for safekeeping.
From the late 1980s through the early 2000s, the number of survivors was reduced to Superman himself in the comic book stories (the Eradicator was added in 1989 as a non-sentient device, and shown to be self-aware in 1991), but more recent accounts have restored Supergirl, Krypto, and Kandor and introduced another newly discovered survivor, Karsta Wor-Ul.
Kryptonian civilization's reported level of technological advancement has also varied. Some works, such as Kevin J. Anderson's novel The Last Days of Krypton, describe it as a few centuries ahead of Earth, while others, such as the Superman film series and Man of Steel, describe it as thousands or even hundreds of thousands of years more advanced.