Paris On The Amazon.

The last remote and pristine forest on our distressed and overcrowded earth" is how Greenpeace describes the Amazon River Valley. For decades now, this romantic view of the Amazon, as a vestige of the once free land corrupted by the arrival of Europeans in the 15th century, has persisted in the popular imagination. Scientists also assumed, without evidence to the contrary, that indigenous tribes tiptoed their way through the forest, living their lives while leaving nature almost completely undisturbed. Human settlements and the grab for gold and timber, they thought, came to the world's largest rain forest only in the last few hundred years.

Now scientists are painting a radically different picture of the Amazon's prehistory. Long before Christopher Columbus dropped anchor in the New World, indigenous tribes were breaking ground on their version of Paris on the Amazon. They burned and chopped down swaths of rain forest to make way for majestic boulevards and circular plazas. They built networks of dikes, ponds and bridges and cleared acres of farmland to grow piqui, a palm fruit, and manioc, a cousin of the potato. Although they lived in mud and thatch huts and relied on their feet, not on animals or even carts, for transportation, their architectural vision rivaled that of the 19th-century Parisian planner, Baron Haussmann. "There was no pristine forest," says Michael Heckenberger, an archeologist at Florida State University in Gainesville and author of a study last week in the journal Science. "No part of it was untouched, unclaimed by human hands. What was there was left intentionally."

Heckenberger reached this conclusion after spending the past 12 years traveling with two Xinguano chiefs, whose names appear as coauthors, through the upper reaches of the Xingu, a sparsely settled tributary of the Amazon that flows through northeastern Brazil. They unearthed centuries of lost tribal history: dark, charcoal-rich earth and bits of ceramics marking the sites of old villages and ...