Action Comics #242

In outer space, Superman encounters a flying saucer carrying Brainiac, a green-skinned super-villain who miniaturizes whole cities--including New York, Paris, Rome, and Metropolis--and places them in bottles aboard his spacecraft, ostensibly for the purpose of enlarging them on his homeworld, which he says has been depopulated by a plague. Superman cannot penetrate Brainiac’s force-barrier, but he arranges to be in Metropolis when it is miniaturized so that he can be taken within his foe’s flying saucer. Superman investigates another bottle city, is surprised to find that he loses his powers within it, and soon learns that it is the miniaturized Kryptonian city of Kandor. Professor Kim-Da, Jor-El’s college roommate, consults with Superman and helps him break out of the bottle while Brainiac sleeps in suspended animation. The miniaturized Superman is able to use a device of Brainiac’s to restore and return the captive cities, but only one charge remains, which can either enlarge him or Kandor, not both. Superman decides to enlarge Kandor, but Kim-Da, in a spacecraft, hits an activator button and enlarges Superman. Kim-Da tells Superman that he could not allow Earth to be deprived of its greatest super-hero. Superman flies away from Brainiac’s saucer with the bottle-city of Kandor, and installs it safely in his Fortress of Solitude.