"The Gods of Pegāna: The Bird of Doom and The End" by Lord Dunsany

Trehagobol, described a couple stories back (in the story entitled "Pegana"), is one of the three great mountains of Pegana, indeed the highest of the three.

The picture used is "The End of Time" by mumu0909, used here under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported license (https://creativecommons.org/licenses/by-nc-nd/3.0/).

The follow along: https://gutenberg.org/cache/epub/8395/pg8395-images.html#THE_BIRD_OF_DOOM_AND_THE_END