For a scenic browse, and an answer-page for Guess The World...
...Half-seen, a dim unhorizoned landscape, fitfully lit by the crimson far-sundered flares of volcanoes, by bluish zones and patches of strange radio-active minerals, it deepened beneath them abysmally disclosing mountains that would have made the Himalayas seem like hillocks, revealing chasms that might have engulfed asteroids and planets.
the center of this Cyclopean landscape burned the great volcano that
had been called Hephaestus by astronomers... Tongues of flame a hundred
miles in length arose and licked skyward from a crater than seemed the
mouth of some ultramundane hell...
Clark Ashton Smith, Phoenix (in Time to Come, ed. August Derleth (1954))
...The tremendous interplay of magnetic and electrostatic fields just beyond the city's edge was as clearly perceptible to his senses as the city itself - a mile-wide disc ringed with conical field towers, stretching away behind and to each side. The ship was poised between two of the towers; immediately behind it was the field from which Kron had just taken off. The area was covered with cradles of various forms - cup-shaped receptacles which held city craft like Kron's own: long, boat-shaped hollows wherein reposed the cigarlike vessels which plied between the cities...
the landing field was the city proper; the surface of the disc was
covered with geometrically shaped buildings - cones, cylinders, prisms,
and hemispheres, jumbled together...
Hal Clement, Proof (Astouonding, June 1942)