'Lost Valley of Cities' Found in Amazon

After many years of research, French archaeologist Stéphen Rostain can deliver a very satisfying "I told you so" to people who told him there was no point in searching for ancient civilizations in the Amazon rainforest. Rostain and fellow researchers say they have discovered a "lost valley of cities" in the rainforest in western Ecuador that was once home to at least 10,000 people and possibly many more, the AP reports. In a study published in the journal Science, the researchers say ground excavations and light detection and ranging —LiDAR—technology revealed a landscape of "clusters of monumental platforms, plazas, and streets," along with an extensive road network connecting the cities.

Researchers say the site is older than anything else detected in the Amazon and "garden urbanism" is unlike anything found in the region before. "It changes the way we see Amazonian cultures," says study co-author Antoine Dorison, per the BBC. "Most people picture small groups, probably naked, living in huts and clearing land—this shows ancient people lived in complicated urban societies." Researchers say the site was occupied from around 500 BC to between 300 and 600 AD. "Imagine that you discovered another civilization like the Maya, but with completely different architecture, land use, ceramics," says José Iriarte, a professor of archaeology who was not involved with the research.

Rostain says the civilization probably flourished because of a "conjunction of good vibes" at the site in the foothills of the Andes, with rich volcanic soil, Scientific American reports. He says he detected earthen mounds in the area decades ago but the vast extent of the civilization wasn't known until LiDAR technology, which uses sensors on planes, could spot structures and roads through dense rainforest. Rostain, director of investigations at France's National Centre for Scientific Research, says he was warned early in his career that he wouldn't find ancient civilizations in the Amazon. "But I'm very stubborn, so I did it anyway," he says. "Now I must admit I am quite happy to have made such a big discovery." (More archaeology stories.)