NEW YORK (AP) Researchers have found a complex of slabs and stones in the Sahara Desert that might be the oldest known monument built with astronomical considerations in mind, said a report published Thursday.
Far older than England's Stonehenge, it was constructed by nomadic cattle herders as many as 7,000 years ago in southern Egypt, and probably was intended for rituals rather than observation of the sky, said McKim Malville of the University of Colorado at Boulder.
An expert in ancient astronomy said that it would be among the oldest astronomical monuments known, but because the ages of such monuments are uncertain, it's impossible to know if the Egyptian complex is the oldest. Additionally, he said the study presents suggestive evidence, but not. proof, for astronomical design.
Malville, an astrophysics professor, describes the stone complex in this week's issue of the journal Nature with anthropologist Fred Wendorf of Southern Methodist University in Dallas and other researchers. The monument was discovered over several years of field work ending in 1997.
Stonehenge was first used about 5,000 years ago and gained some of its current stones about 4,000 years ago. The stones indicate the points of midsummer sunrise and midwinter sunset, but nobody knows just what people used Stonehenge for and the complex's exact role remains unknown.
The Egyptian stone complex, which is not circular like Stonehenge, is spread over an area of 2.9 km by 1.2 km. It includes 10 slabs about 2.7 meters high, 30 rock-lined ovals, nine burial sites for cows, each under a pile of 40 to 50 rocks weighing between 90 or 140 kg apiece, and a "calendar circle" of stones.
Many of these features line up in five radiating lines, one of them running east-west.

SAHARA DESERT, Egypt—These stone slabs in southern Egypt in the Sahara Desert might be the oldest known monument built with astronomical considerations in mind. The complex, shown In this undated file photo, was constructed by nomadic cattle herders as many as 7,000 years ago. AP PHOTO