Angkorian hydraulic reservoir in Siem Reap province, Cambodia

An aerial view over Banteay Srey temple, one of the many stone monuments built during the Angkorian period, in Siem Reap province, Cambodia, on Wednesday Jan. 23, 2008. An international research group is now trying to dig up answers to the question about Angkorian hydraulic network as part its quest to shed more light on the puzzles left since the demise of the Angkor city centuries ago.

Australian archaeologists Damian Evans, left, and Roland Fletcher, right, study a map of Angkorian city during a tour of excavation site in Siem Reap province, Cambodia, on Wednesday Jan. 23, 2008. An international research group is now trying to dig up answers to the question about Angkorian hydraulic network as part of its quest to shed more light on the puzzles left since the demise of the Angkor city centuries ago.

A Cambodian man works on a jungle-covered temple north of Siem Reap province, Cambodia, on Tuesday Jan. 22, 2008. An international research group is now trying to dig up answers to the question about the Angkorian hydraulic network as part of its quest to shed more light on the puzzles left since the demise of the Angkor city centuries ago.

Roland Fletcher, an Australian archaeology professor, points to a map of Angkorian hydraulic reservoir in Siem Reap province, Cambodia, on Wednesday Jan. 23, 2008. An international research group is now trying to dig up answers to the question about the Angkorian hydraulic network as part of its quest to shed more light on the puzzles left since the demise of the Angkor city centuries ago.