"Nabta Playa is an internally drained basin that served as an important ceremonial center for nomadic tribes during the early part of the Holocene epoch. Located 100 km west of Abu Simbel in southern Egypt, Nabta contains a number of standing and toppled megaliths. They include flat, tomb-like stone structures and a small stone circle that predates Stonehenge and other similar prehistoric sites by at least 1000 years.
The site was first discovered in 1974 by a group of scientists headed by Fred Wendorf, an Anthropology Professor from Southern Methodist University in Texas. The team had stopped for a break from their uncomfortable drive from the Libyan border to the Nile Valley when, as Wendorf stated, “we were standing there minding our own business, when we noticed potsherds and other artifacts." Throughout the 1970’s and 1980’s, Wendorf returned to Nabta several times. He determined that humans had occupied the Nabta area off and on for thousands of years, dating from as early as 11,000 years ago up until about 4,800 years ago. Although the area was occupied for more then 5,000 years, the majority of the stone structures and other artifacts originated between 7,000 and 6,500 years ago. It was considered by most to be the height of human occupation at Nabta.
Nabta became a habitable area because of a climatic change that occurred over North Africa around 12,000 years ago. This climatic change was caused by a northward shift of the summer monsoons. This shift brought enough rain to the Nabta region to enable it to sustain life for both humans and animals. Although it was a small amount of rain, usually around four to eight inches (10-15 cm) per year, it was enough to fill the playas with water for months at a time. Between 11,000 and 9,300 years ago, Nabta saw its first settlements. The people living at Nabta herded cattle, made ceramic vessels, and set up seasonal camps around the playa. These people regarded cattle in much the same way as modern peoples of West Africa regard them. The blood and milk of the cattle was more significant than the meat. The ceramics that were found from this period are minimal, but are considered to be some of the oldest identified in Africa . . ."
continued at link http://www.mnsu.edu/emuseum/archaeology/sites/africa/nabtaplaya.html