According to the Heliopolitans, the first act of creation occurred when the sun god Atum, "lord of Heliopolis", rose out of the chaos of Nun from a lotus flower and stood on a raised mound he created, the ben-ben. This first act of creation brought light into the world. At the site of his emergence, the temple of Heliopolis was built. Atum was called a self-created god or the child of Nun. He was also said to be the ben-ben. At the time of the Pyramid Texts, Atum became identified with Re. As Atum-Re, he was connected to the Bennu bird (the phoenix).

Atum created his children, Shu and Tefnut by masturbating. This may seem impossible but Atum was a bisexual god. He embodied both the male and female aspects of life. Therefore, his semen contained all that was necessary to create new life and deities. The Egyptians called Atum "Great He-She" and his name meant "the complete one".

Shu and Tefnut in turn conceived Geb and Nut through normal sexual relations. Geb was the god of the earth and Nut was the sky. After conceiving four children (Osiris, Isis, Nephthys, and Seth), Geb and Nut became separated by their father Shu, the god of the air. Nut is often shown arched over Geb with the sun traveling along her body. Beyond Nut's body lies Nun and nonexistence.