Subterranea
Subterranea is an underground kingdom ruled by the Shah, reached by the Skyrocket's crash.
First named in The Yellow Knight of Oz, ch. 7
"You are in Subterranea."
Where this is
placed Beyond the desert worked out
read out of the chapters cited on this page, not stated in any one sentence of them
What the books say it is
appearance chill, heavy air 1 chapter
The chill, heavy air of Subterranea seemed to clear and brighten.
The Yellow Knight of Oz, ch. 8