George MacDonald's The Princess and the Goblin takes place in a sort of castle, midway on a mountain:
There was once a little princess whose father was king over a great country full of mountains and valleys. His palace was built upon one of the mountains, and was very grand and beautiful. The princess, whose name was Irene, was born there, but she was sent soon after her birth, because her mother was not very strong, to be brought up by country people in a large house, half castle, half farm-house, on the side of another mountain, about halfway between its base and its peak.This home is like a station of the "ordinary" between realms below and above it that are, in contrast, the true realities: the realms of goblins and heavenly great-great-grandmothers.
These mountains were full of hollow places underneath; huge caverns, and winding ways, some with water running through them, and some shining with all colors of the rainbow when a light was taken in. There would not have been much known about them, had there not been mines there, great deep pits, with long galleries and passages running off from them, which had been dug to get at the ore of which the mountains were full. In the course of digging, the miners came upon many of these natural caverns. A few of them had far-off openings out on the side of a mountain, or into a ravine.But above, staircase after staircase in the big house-castle lives Irene's great-great Grandmother - without the wrinkles of age you would expect on such a face. To all others, this heavenly mother is non-existent. Once, even Irene has doubts about what is the true reality. But no, the great grandmother has been up there the entire eight years that Irene has been living in the place; just that in all those years, Irene had never gone up all those stairs, and never explored the empty hallways.
Now in these subterranean caverns lived a strange race of beings, called by some gnomes, by some kobolds, by some goblins.
One gets the sense of greater places, of everlasting places, just, just beyond those you are familiar with, when Irene stands in the door and sees this woman for the first, and the grandmother simply says, as though there were no need for any introduction:
"Come in, my dear; come in. I am glad to see you."