The Night Land is typically assumed to be either a work of fantasy, or one of horror. I will argue that it is Science Fiction.
"I have done my duty," she said quietly, the words snatched by the relentless wind.
"There had been other occasions when she'd caught the echoes of an undersong within the aether; but not before tonight had its tones carried strongly enough for her to know that she had not imagined it."
A combination of known planetary geology, climatology, evolution, etc. Conjectures range about 20-50 million years into the future.
"I in my tower, staring out, with that keen dread sense telling me of the vast presences outside, and of their slow, deliberate ranging toward my house..."
"He still walks the Night Lands — alive, human. I must go to him, bring him back."
Copyright 2001–2015 by Andy Robertson, Kate Coady, Tais Teng, Martin Isitt, Stephen Fabian, et alii.