The ancient Khmer city of Angkor in Cambodia was the largest preindustrial metropolis in the world, with a population near 1 million and an urban sprawl that stretched over an area similar to modern-day Los Angeles, researchers reported Monday.
The city's spread over an area of more than 115 square miles was made possible by a sophisticated technology for managing and harvesting water for use during the dry season -- including diverting a major river through the heart of the city.
For The Record
Los Angeles Times Wednesday, August 15, 2007 Home Edition Main News Part Page News Desk 1 inches; 52 words Type of Material: Correction
Angkor: A photo caption in Tuesday's Section A with an article about the ancient Khmer city of Angkor in Cambodia said the temple in the photo was Angkor Wat. It was the Bayon temple. The article also gave the area of the city as 115 square miles. It is 1,350 square miles.
But that reliance on water led to the city's collapse in the 1500s as overpopulation and deforestation filled the canals with sediment, overwhelming the city's ability to maintain the system, according to the report in the Proceedings of the National Academy of Sciences.
The hydraulic system became "not manageable, no matter how many resources were thrown at it," said archeologist Damian Evans of the University of Sydney in Australia, the lead author of the paper.
But during the six centuries that the city thrived, it was unparalleled, particularly because it was one of the very few civilizations that sprang up in a tropical setting, said archeologist Vernon L. Scarborough of the University of Cincinnati, who was not involved in the research.
Just one section of the city, called West Baray, was many times "larger than the entire 9-square-kilometer hillock on which sat Tikal, the largest city in Central America," he said.
"The scale is truly unparalleled," added archeologist William A. Saturno of Boston University, who also was not involved.
"Forest environments are not good ones for civilizations . . . because they require intensively manipulating the environment," he said. "Angkor is the epitome of this, and it is going to be the model for how tropical civilizations are interpreted."
Old and new technologies
The new data come from an unusual agglomeration of both old and new technologies. The core data came from a synthetic aperture radar unit flown on the space shuttle in 2000 and managed by NASA's Jet Propulsion Laboratory in La Cañada Flintridge.
The radar pierced low-lying clouds and vegetation to give an accurate picture of soil density, local structures and moisture in soil, which reflects growing conditions.
The images revealed, for example, the characteristic moat-enclosed local temples and artificial ponds used for water storage and irrigation.
