A common trope in boy’s own adventure type fantasy stories and sci-fi is finding hidden or lost cities in the middle of jungles, on mountain tops or some other remote location. Quite often there is no evidence that these cities exist until you literally run into the gate, despite the fact a large city would need hundreds of square miles of farm land to feed its population
- Apocalypto: we do see one corn field but it’s really small and there’s open jungle beyond it
- Doctor who: where do the dome cities in genesis of the daleks get their food?
- in one episode Jackie Chan Adventures Jackie discovers the Lost City of the Muntabs, which appears to be a fully populated city just in the middle of open jungle wilderness