A mirage occurs when light rays bend between air layers of different temperatures. In this case, light rays produce a displaced image of distant objects or the sky.

There are several types of mirages. For example, a lower mirage (like in the picture): looks like a sparkling water surface in a desert, when in fact it’s just the sky’s reflection above the overheated sandy ground.

Higher mirages are common for the northern regions since there are big and flat ice floes. Maybe thanks to this effect, Icelanders discovered Greenland.