With the help of high-tech lasers, a group of archaeologists scanned the Cambodian jungle. Led by Damian Evans, the team discovered signs of large networks around the huge stone temple complex. These findings are expected to not only further our understanding of Khmer culture, but also give the reasons for the 15th-century decline of the empire.

A laser technology called lidar helped the team to make precise maps of the old networks, pinpointing just a few signs of the landscape that are not too visible.

"You could be standing in the middle of the forest looking at what appear to be some random lumps and bumps," Evans said. "But they might actually be evidence of old excavated ponds or built-up roadways," he explained. "All of these things left traces on the surface of the landscape that wouldn't make sense to you without a more detailed picture."

Hence, the team would be helicoptering for 90 hours, scanning the jungle, and getting images so fine and intricate that "you can see objects lying next to a tiny anthill."

The research was published Monday in the Journal of Archaeological Science. They study is a joint project including the French Institute of Asian Studies in Paris, the Cambodian national authority responsible for protecting Angkor Wat and the ministry of culture and fine arts.

The ancient Khmer civilization was thought to have been damaged in the 15th century by Thai armies that sacked Angkor Wat. It forced large populations to shift to southern Cambodia. However, Evans explained that their maps did not indicate signs of dense cities in the south. Hence, there was no mass migration.

Chanratana Chen, a Cambodian academic at the University of Sorbonne in Paris, who was not involved in the research, said that the new findings have altered his entire perception of the Angkor Wat temple complex or the "the small city."

"The new results (show) us that Cambodia was a much more advanced civilization than we thought, especially about the management plan of the city and irrigation system to improve agriculture in the area," Chen wrote in an email. Evans and colleagues found medieval sandstone quarries and some signs of a royal road between various temple complexes.