In Egyptian belief, the disorder that predates the ordered world exists beyond the world as an infinite expanse of formless water, personified by the god Nun. The earth, personified by the god Geb, is a flat piece of land over which arches the sky, usually represented by the goddess Nut. The two are separated by the personification of air, Shu. The sun god Ra is said to travel through the sky, across the body of Nut, enlivening the world with his light. At night Ra passes beyond the western horizon into the Duat, a mysterious region that borders the formlessness of Nun. At dawn he emerges from the Duat in the eastern horizon.