Metropolis

Metropolis was a location which appeared in the Superman comic book series.

In an issue of the comic read by the Twelfth Doctor, there was a mystery in Metropolis involving a spaceship and unoccupied hibernation pods. Superman thought it may have been some kind of drone ship or a robot probe. (TV: The Return of Doctor Mysterio)

Behind the scenes

 * Metropolis appeared as a location in Lego Dimensions.