Peru's coastal desert, one of the most parched places on Earth, has given birth to a succession of early civilizations. Now, archaeologists have discovered that inland settlements there were even more important early on than most archaeologists had realized. "It looks like Caral is really the first complex society in the New World," says Jonathan Haas, a co-author of the paper and an archaeologist at the Field Museum in Chicago.
The site is called Caral, located some 200 kilometers north of Lima and 23 kilometers from the Pacific Ocean. It was the architectural wonder of its day in the Americas. At its apogee, it boasted eight sectors of modest homes and grand stone-walled residences, two circular plazas, and six immense platform mounds built from quarried stone and river cobbles. Huge warrens of ceremonial rooms, which probably served as symbols of centralized religion, crowned the mounds.
To determine the age of these structures, archaeologist Ruth Shady Solis of the National University of San Marcos in Lima and her associates obtained carbon-14 dates on 18 excavated plant samples from the site. In the 27 April issue of Science , they report that the buildings date back to 2627 B.C.--pushing back the emergence of urban life and monumental architecture in the Americas by nearly 800 years. "The team has got very nice dates that we can associate with a specific human event," such as the building of the mounds, says Brian Billman, an archaeologist at the University of North Carolina, Chapel Hill.
The new dates cast doubt on the theory that Peru's civilizations originated on the coast. This popular idea holds that huge schools of fish and shellfish beds permitted early fishers and foragers to settle along the coast, build elaborate architecture, and develop complex societies, moving inland only later. But Caral is centuries older than any other large urban center. "Rather than coastal antecedents to monumental inland sites," says archaeologist Shelia Pozorski of the University of Texas-Pan American in Edinburg, "what we have now are coastal satellite villages to monumental inland sites."
Exactly what fueled the early construction boom at Caral is still unclear, but the excavators say the geography of the river valley would have made it easy to practice irrigation agriculture.