The Benben stone is an architectural name given to the tip of an obelisk or the capstone placed on top of a pyramid. This architectural feature is known also as a pyramidion. Also the Benben stone is a symbol of the Phoenix and the cycle of the seasons. 
Egyptian mythology has many stories of the creation, one says the god Atum, brought the universe into being. In the beginning, there was nothing but darkness and chaos. It was out of the dark waters that the primordial hill, known as the Benben stone arose with Atum on top of it.
In some versions of the myth, Atum masturbated, creating Shu and Tefnut. In other versions of the story, they were created by Atum’s copulation with his own shadow. Shu and Tefnut left Atum on the Benben stone, and went away to create the rest of the world.
After a while, Atum grew worried about his children, removed his eye and sent it in search of them. Shu and Tefnut returned with the eye, and Atum, seeing his children return shed tears of joy. The teardrops fell on the Benben stone Atum was on and transformed into human beings.
