While studying nomads camped some 600 miles south of Cairo about 20 years ago, Fred Wendorf noticed groups of large stones near the camp. He thought the stones were bedrock outcrops and didn't take much interest in them. Only in 1990, on a return trip, did he take a closer look. Then he realized that the stones lay on the site of an ancient lake bed and must have been brought there. Curious, he began excavating. Eight years and much digging and surveying later, Wendorf, an anthropologist at Southern Methodist University, announced that the stone slabs he had unearthed--some standing nine feet tall--are among the oldest astronomical alignments of megaliths in the world. Erected 7,300 to 6,800 years ago, they predate Stonehenge by more than 1,000 years and may have been built by a nomadic society that later settled and gave rise to early Egyptian civilization.
At the site--called Nabta Playa (Nabta means "little bushes" in Arabic, and playa refers to a basin that holds water seasonally)--is a 12-foot-wide circle of stones formed by four pairs of large upright slabs. Two pairs line up north-south, and the other two pairs lie east-northeast to west-southwest. The sunrise on the summer solstice could have been sighted along the latter pairs 6,800 years ago, says Wendorf.
Wendorf also found an unusual tomb. When he discovered the tomb--a roofed, clay-lined chamber about 25 feet wide--he had hoped it might hold the remains of a ruler. But the tomb contained only cattle bones. Wendorf says the burial suggests that the megalith builders were a nomadic, cattle-raising people like the Masai.
The site may have been built to commemorate the arrival of the summer monsoons. Between 11,000 and 4,800 years ago, monsoons swept north from Central Africa and formed temporary lakes in southern Egypt. When the lakes dried up, the nomads moved on, only to return the next year. If the nomads did go on to found the first civilization in the Nile Valley, says Wendorf, "it could explain the religious significance that Egyptians attached to the cow and cattle in the Old Kingdom."