In Focus

05 December 2008 04:43 BST

Ancient Angkor

An ancient urban scrawl including 74 temples once existed around the temple of Angkor Wat in Cambodia, radar and ground surveys have revealed.

The majestic Hindu temple was built in the 12th century for the King Suryavarman II and is listed on the World Heritage List.

An international team of archaeologists discovered that ancient settlements were once built over 1,000 sq km and were linked by a complex irrigation system.

Included in the settlements were over 1,000 man-made ponds and at least 74 long-lost temples. Two massive earthen structures, whose precise function remains unknown, once existed east of the East Baray and to the south-west of Phnom Dei.

To make the discovery the team spent years studying the area using hand-drawn maps, ground surveys, photographs taken from aircraft and ground-sensing radar provided by Nasa.

The radar sensed differences in plant growth and moisture content that result from topographical variations of less than a metre.

Writing in the journal Proceedings of the National Academy of Sciences, the scientists argue that the discovery of the past size and settlement of Greater Angkor has important cultural implications.

"Even on a quite conservative estimate, Greater Angkor, at its peak, was the world's most extensive preindustrial low density urban complex. This has substantial implications for heritage management, as the well-preserved remains of the urban complex extend far beyond the designated World Heritage zone that surrounds the central temples," the researchers claim.

They argue that further studies of the site are "critical" as "similar discoveries in these locations would transform our understanding of their social, cultural, and environmental contexts".

"This, in turn, will provide a foundation for comparative studies of the great cities that emerged and then collapsed in fragile tropical ecosystems, an important and topical field of research that has received minimal attention thus far," they conclude.