Ogre of Fire's castle
The Ogre of Fire's castle was a castle featured in one of the stories from The Adventures of Flotter series of holoprograms, wherein it functioned as the home of the Ogre of Fire. 

In the story, it hovered over the Forest of Forever, and was described as a "great black spaceship" taller than the tallest tree in the forest. The method of entry to the castle for Flotter and Trevis, who were working together at stopping the ogre from burning the forest, was through a mysterious door that appeared in a clearing. ()
Fictional locations
The Adventures of Flotter