George MacDonald 
The Princess and the Goblin 

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 farmhouse, on the side of another mountain, about half-way between its base and its peak.
The princess was a sweet little creature, and at the time my story begins was about eight years old, I think, but she got older very fast. Her face was fair and pretty, with eyes like two bits of night sky, each with a star dissolved in the blue. Those eyes you would have thought must have known they came from there, so often were they turned up in that direction. The ceiling of her nursery was blue, with stars in it, as like the sky as they could make it. But I doubt if ever she saw the real sky with the stars in it, for a reason which I had better mention at once.
These mountains were full of hollow places underneath; huge caverns, and winding ways, some with water running through them, and some shining with all colours 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.