Great A'Tuin, the World Turtle, was the gigantic turtle upon whose back the Discworld was carried through space. The Disc does not rest directly on A'Tuin; instead, it rests on the shoulders of four immense elephants, Berilia, Tubul, Great T'Phon and Jerakeen, who stand atop the turtle's shell.
Many things remained unknown about Great A'Tuin, including its gender and desires. These were matters of constant speculation by philosophers, mystics and theologians. It is known that A'Tuin was not the only World Turtle, however.