There’s a cafe near my work called The Hidden City.
Seems like there has to be a place in any campaign world for The Hidden City. It could be
-in the mountains, a la Shangri La
-subterranean, a la Neverwhere
-walled, a la the Forbidden City
-magically nestled in another city, a la Diagon Alley, or Rowling’s obvious literary inspiration, that one Gord the Rogue short story
-tiny: maybe a city of sentient bugs, or ratlings