Located deep in the Nubian desert, the Nabta Playa stone circle holds astonishing details of ancient astronomy. Located 500 miles south of Cairo, deep in the Nubian desert, is one of the oldest stone circles in the world. Research has revealed that the Nabta Playa complex dates before Predynastic Egyptian history. In addition to the relatively large-scale settlement plan of a seasonal nature, several wells have been discovered, along with unique formations of worked stones. A significant mystery has been unfolding in regards to ancient astronomical knowledge and the strange location of this site. Who built it and why? More from Mad Malloy.