In Arthur C. Clarke’s “The City and the Stars,” the eternal city is called Diaspar.
Diaspar is an enclosed, technologically maintained city on a far-future Earth. Its inhabitants believe humanity has been driven back from the stars by terrifying invaders, so they preserve a highly controlled civilization and avoid contact with the outside world. The city’s Central Computer creates bodies, stores minds, and helps maintain the illusion of continuity across generations.
The main character, Alvin, is unusual because he is a “Unique”: unlike nearly everyone else in Diaspar, he has no memories of previous lives and feels compelled to explore beyond the city. His journey reveals another surviving human settlement, Lys, whose natural, agrarian culture sharply contrasts with Diaspar’s machine-centered society.
Clarke published the novel in 1956 as a major rewrite of his earlier 1948 story “Against the Fall of Night.” Diaspar is sometimes confused with Lys, the other major human settlement, or Shalmirane, an ancient site connected to Earth’s forgotten history. The novel is set at least 2.5 billion years in the future.