A Mystery 1,000 Years Older Than Stonehenge

Other studies have shown that human beings thrived in the Sahara for 100,000 years or more in areas now virtually uninhabitable. For instance, scientists have discovered the earliest known observatory for marking the movement of the stars, which ancient people could have used in religious ceremonies and in planning their migrations and crop plantings. Some 6,500 years ago at Nabta in Egypt, ancient people somehow positioned in a circle a series of flat, tomblike stone structures to which they connected five lines of now-toppled stone monoliths. These vanished Sahara dwellers positioned their heavy stone monuments a full 1,000 years before the mysterious builders of Stonehenge in England. The ruins lie on the shoreline of an ancient lake that filled some 11,000 years ago, but dried up an estimated 4,800 years ago. Beneath one of the stone structures researchers found a rock carved into the shape of a cow standing upright. They also found several ritually buried cows, laid reverently to rest in a roofed, clay-lined chamber. The stone circle measures 12 feet (4 m) in diameter, with alignments that apparently mark the position of the sun on summer solstice, the longest day of the year. The alignment of the stones also point to two stone megaliths about a mile away, although scientists still do not fully understand the significance of some of the alignments. The ancient observatory was right on the shore of the lake and may have been designed to mark the high-water mark of the lake’s seasonal expansion. The researchers noted that it now appears that the desert-dwellers who arranged the stone monoliths at Nabta may have moved to the banks of the Nile River as the Sahara dried, perhaps in their movement fostering the emergence of the Egyptian civilization, one of the first, irrigationbased civilizations in human history.