Celestial Find at Ancient Andes Site

The observatory was built on the top of a 33-foot-tall pyramid with precise alignments and sightlines that provide an astronomical calendar for agriculture, archeologist Robert Benfer of the University of Missouri said.

The people who built the observatory -- three millenniums before the emergence of the Incas -- are a mystery, but they achieved a level of art and science that archeologists say they did not know existed in the region until at least 800 years later.

Among the most impressive finds was a massive clay sculpture -- an ancient version of the modern frowning "sad face" icon flanked by two animals. The disk, protected from looters beneath thousands of years of dirt and debris, marked the position of the winter solstice.

"It's really quite a shock to everyone

The find adds strong evidence to support the recent idea that a sophisticated civilization developed in South America in the pre-ceramic era, before the development of fired pottery sometime after 1500 BC.

Benfer's discovery "pushes the envelope of civilization farther south and inland from the coast, and adds the important dimension of astronomy to these ancient folks' way of life," said archeologist Michael Moseley of the University of Florida, a noted Peru expert.

The 20-acre site, called Buena Vista, is about 25 miles inland in the Rio Chillon Valley, just north of Lima. "It is on a totally barren, rock-covered hill looking down on a beautiful fertile valley," said Benfer, who presented the find last month in Puerto Rico at a meeting of the Society for American Archeology.

The site is remarkably well preserved, Benfer said, because it rains in the area only about once a year.

The name of the people who inhabited the region is unknown because writing did not emerge in the Americas for 2,000 more years. Some archeologists call them followers of the Kotosh religious tradition. Others call them late pre-ceramic cultures of the central coast. For brevity, most simply call them Andeans.

Benfer and archeologist Bernardino Ojeda of Peru's National Agrarian University have been working at Buena Vista for four years. The site contains ruins dating from 10,000 years ago to well into the ceramic era in the first millennium BC.