World Turtle

Various ancient cosmologies held that the world rests on the back of a turtle, or on an elephant, or is perhaps contained in the shell of a turtle (with the earth being the lower shell and the sky the upper shell. Some westerners mixed these myths together to say that Hindus believe that the earth rests on four elephants who stand on the back of a giant turtle, and this was repeated by Bertrand Russel. This doesn't really fit Hindu myths, but there is a story where the gods and demons were churning the ocean of the milky way with a mountain that started sinking, so Vishnu came in the form of a tortoise and supported the mountain on his back. Even though a corruption of the ancient myths, this elephants and tortoise picture is a potent one (and I assumed it came from actual ancient myths), and it shows up in the Discworld novels, as shown here by zgrredek.