A Silver Age Superman was not alone in the survival of Krypton's destruction, being joined by his cousin Supergirl, the Phantom Zone criminals, Beppo the Super-Monkey, Krypto the Superdog, a juvenile delinquent named Dev-Em, the entire population of the city of Kandor, Supergirl's biological parents, and even Superman's biological parents (in hibernation on a space ship - "Superboy" #158 (July 1969)), although it was discovered that they actually died from lethal radiation. When the planet exploded, one entire city of Krypton, Argo City, survived the cataclysm.