Mirages (photos above and below by TheBrockenInaGlory) come in two varieties – inferior (like the one above) and superior. Inferior mirages are quite common, often showing an image of the sky that gives the illusion of a lake or pool of water. Inferior mirages result from refraction by hot air near the ground.
Superior mirages (like the one below) result from refraction by cold air near the ground, and are more commonly seen in the Arctic and Antarctic. Complex superior mirages (or Fata Morgana) can contain multiple images of the original object, often distorted, and both inverted and right side up.
The complex superior mirages seen near the poles are mentioned in H. P. Lovecraft’s classic horror novel At the Mountains of Madness:
“Our early flights were disappointing … though they afforded us some magnificent examples of the richly fantastic and deceptive mirages of the polar regions, of which our sea voyage had given us some brief foretastes. Distant mountains floated in the sky as enchanted cities, and often the whole white world would dissolve into a gold, silver, and scarlet land of Dunsanian dreams and adventurous expectancy under the magic of the low midnight sun. … I had seen dozens of polar mirages during the preceding weeks, some of them quite as uncanny and fantastically vivid as the present sample; but this one had a wholly novel and obscure quality of menacing symbolism, and I shuddered as the seething labyrinth of fabulous walls and towers and minarets loomed out of the troubled ice-vapours above our heads.
The effect was that of a Cyclopean city of no architecture known to man or to human imagination, with vast aggregations of night-black masonry embodying monstrous perversions of geometrical laws and attaining the most grotesque extremes of sinister bizarrerie. There were truncated cones, sometimes terraced or fluted, surmounted by tall cylindrical shafts here and there bulbously enlarged and often capped with tiers of thinnish scalloped discs; and strange, beetling, table-like constructions suggesting piles of multitudinous rectangular slabs or circular plates or five-pointed stars with each one overlapping the one beneath. There were composite cones and pyramids either alone or surmounting cylinders or cubes or flatter truncated cones and pyramids, and occasional needle-like spires in curious clusters of five. All of these febrile structures seemed knit together by tubular bridges crossing from one to the other at various dizzy heights, and the implied scale of the whole was terrifying and oppressive in its sheer giganticism. The general type of mirage was not unlike some of the wilder forms observed and drawn by the Arctic whaler Scoresby in 1820; but … we all seemed to find in it a taint of latent malignity and infinitely evil portent. … I was glad when the mirage began to break up, though in the process the various nightmare turrets and cones assumed distorted temporary forms of even vaster hideousness.”
Scientific Gems 