Celephaïs

A city of ivory and bronze that has not aged a day since a homesick English boy first dreamed it into being, later returning as its permanently installed ruling god. The Archive notes this as one of the more enviable outcomes on file, assuming the arrangement is as permanent as it currently appears.

Whereabouts: A city of minarets and galleys in the Valley of Ooth-Nargai, beyond the Tanarian Hills — reachable, by the one detailed account on file, only by the dreamer who first found it as a child.

Access: By dream alone, and apparently only reliably for the one dreamer who first found it; later visits required progressively stronger measures to induce the correct sleep.