The Discworld itself - a flat, circular world resting on the backs of four enormous elephants (Berilia, Tubul, Great T'Phon, and Jerakeen), who in turn stand on the shell of Great A'Tuin, a giant turtle swimming through space. The Disc has a central mountain (Cori Celesti, home of the gods), an Edge over which water falls endlessly, and a tiny orbiting sun. The fundamental absurdity of this cosmology is entirely the point.