They trekked for half a mile, stuffing some 70 pounds of stones collected from the riverbed and surrounding hillsides into open-weave bags made of reeds. Returning to the terrace 80 feet above the river valley, the workers set the rocks, bags and all, inside cut-stone retaining walls that formed the rectangular base of a pyramid that would eventually rise 60 feet. Then they went back for more; the pyramid's base, after all, was bigger than four modern-day football fields. None of this would be particularly remarkable, except for where it was happening--and when. The site, called Caral, lies not in Egypt, but 120 miles north of Lima, Peru, and 12 miles inland from the Pacific Ocean in the foothills of the Andes Mountains. Last week archeologists announced that it dates from 2627 B.C., the same era when Egyptian slaves were building the Great Pyramids and a full 1,500 years before scientists thought urban civilization began in the New World. "This is the oldest human settlement of any social complexity ever found in the Americas," says archeologist Ruth Shady Solis of San Marcos National University in Lima, who led the excavation. Caral may therefore be "the birthplace of New World civilization," says archeologist Winifred Creamer of Northern Illinois University, a member of the team.
Today, Caral is not much to look at. Desert hills covered in sunbaked sand ring a cluster of earthen mounds, which appear no more notable than a bunch of overgrown prairie-dog hills. But appearances deceive. Beneath the windblown sands of time each mound is actually a complex, pyramid-shaped structure built more than 4,000 years ago. Although archeologists knew in 1905 that something once stood at Caral, the site was overlooked in favor of others containing--yes, researchers can be suckers for all that glitters, too--gold.
But when Shady turned to Caral in 1994, she found that it had something even better, as she and her collaborators report in the journal Science. Six pyramids dot the center of the city, along with two sunken plazas; eight residential neighborhoods and numerous smaller "platform mounds" sprawl beyond. Along the terraced sides of the largest pyramid, one eighth the height of the Great Pyramid of Khufu, staircases lead to a flat apex, site of a suite of rooms and fire pit probably used for religious rituals. The five other pyramids may have been the equivalent of a modern city's many houses of worship--or clubs. "The people of Caral were beginning to form social classes, and each stratum of society might have belonged to a different pyramid," says Rocio Aramburu, who was directing excavations last week. Inside the foundation of one, the archeologists found the remains of an 18-month-old boy, reflecting the practice of many pre-Incan peoples of offering a little boy to the gods.
The planning and labor mobilization required to build the pyramids hint that some centralized authority was calling the shots. Each of the six stands amid formally arranged groups of houses--history's first planned communities. Smaller pyramids, each with a flight of stairs leading to rooms with a view, probably housed Caral's elite. A group of adobe homes was probably a middle-class enclave for "craftsmen, people who spun cotton, wove textiles, made tools, managed irrigation or worked for the priests and rulers," Creamer says. On Caral's periphery, structures made of wooden poles, cane and mud were the homes of servants or peasants who farmed cotton, beans, guava and squash, or hauled rocks for the latest temple. "The buildings imply an advanced knowledge of architecture, engineering, geometry--all the mathematical sciences," says Aramburu.
One of Caral's more striking structures is the Temple of the Amphitheater, one of two sunken circular plazas where residents probably gathered to watch religious ceremonies. The temple also boasts an elevated atrium that archeologists suspect was a semiprivate space, reserved for ceremonies of maybe 20 people. "The bulk of the structures are ceremonial," says Aramburu. "If they built something, they did so for religious purposes. We haven't found warehouses for storing food, for example." But they have found signs of irrigation, making Caral one of the first civilizations in the Americas to break free of the whims of the rain gods. Irrigation fed vast fields of cotton, which supported some 3,000 people. That's undoubtedly how Caral managed to thrive in defiance, as it were, of anthropologists' belief that Peru's great civilizations began near the sea and were based on a maritime economy.
You don't live on cotton alone, of course: Caral also cultivated sophisticated trading partnerships. "There was an exchange of technology, food and other commodities," says Shady. Remains of ishpingo, a wood that grows only in the jungle, hints at one trading route; snail shells native to the Amazon Basin (and used to store dyes) reveal another. Bones of anchovies and sardines, as well as clam and mussel shells, show that Caral acquired fish from the coast, probably in exchange for cotton clothing and fishnets.
Caral and the 17 other centers in the Supe River Valley eventually gave rise to the Incas, who ruled the Andes when the Europeans arrived four millenniums later. Excavations continue, as the archeologists try to glean "what these people thought, what they felt, what knowledge they acquired," says Aramburu. "Excavation is like reading the human mind"--which, scientists now know, began to create an urban civilization in the Americas hardly a blink in time after the great cities of Mesopotamia arose in what is now Iraq, and a millennium earlier than the textbooks say.