In cartoons, mirages are elaborate visions of tropical oases, complete with palm trees and ornate swimming pools. They spring up suddenly in the hot desert, and then disappear just as the sun-addled hero is about to dive in. This sort of illusion is complete fiction, of course, but mirages do really exist, and they can make you see water where there isn't any. In hot areas, you see them along the highway all the time.

In this edition of HowStuffWorks, we'll examine the simple scientific principles behind this strange phenomenon. We'll also look at some less common mirages, such as hovering phantom islands and ships.