Angkor Wat at sunset, Siem Reap, Cambodia. Photo: Leslie Ray Ware via Shutterstock

AIRBORNE LASER TECHNOLOGY has uncovered a network of roadways and canals, illustrating a bustling ancient city linking Cambodia’s famed Angkor Wat temples complex.

The discovery was announced late Monday in a peer-reviewed paper released early by the journal Proceedings of the National Academy of Sciences. The laser scanning revealed a previously undocumented formal urban planned landscape integrating the 1,200-year-old temples.

The airborne lasers produced a detailed map of a vast cityscape, including highways and previously undiscovered temples, hidden beneath dense vegetation atop Phnom Kulen mountain in Siem Reap province. It was the lost city of Mahendraparvata.

‘A picture of an entire city people didn’t know was there’

“What we have now with this instrument is just ‘bang’ — all of a sudden, an immediate picture of an entire city that people didn’t know was there before, which is remarkable,” University of Sydney archaeologist Damian Evans, the study’s lead author, told Australia’s The Age in a video interview from Cambodia. “So instead of this kind of very long gradual process, you have this kind of sudden eureka moment where you bring the data up on screen the first time and there it is — this ancient city very clearly in front of you.”

The laser technology, known as lidar, works by firing laser pulses from an aircraft to the ground and measuring the distance to create a detailed, three-dimensional map of the area. It’s a useful tool for archaeologists because the lasers can penetrate dense vegetation and cover swaths of ground far faster than they could be analyzed on foot. Lidar has been used to explore other archaeological sites, such as Stonehenge.

Towers of the legendary Angkor Wat temple are seen north of Siem Reap provincial town, about 230 kilometers, 143 miles, northwest of the capital Phnom Penh, Cambodia, on June 8, 2006. Siem Reap is Cambodia’s main tourist destination where the famed Angkor temples are located and attracting millions of dollars in revenue every year for the poor Southeast Asian nation. (AP Photo/Heng Sinith)

What happened to the civilisation at Mahendraparvata?

In April 2012, the Australian researchers loaded the equipment onto a helicopter, which spent days crisscrossing the dense forests from 800 meters above the ground. The team then confirmed the findings with an on-foot expedition through the jungle.

“We had reasonable expectations, I guess, of what we would find using the lidar data, but what we’ve ended up with has just blown our minds,” Evans told The Age. “It’s just absolutely incredible what we can see.”

The researchers theorise the civilisation at Mahendraparvata eventually collapsed because of deforestation and broken canals and reservoirs.

Detail of carved Sanskrit text on third level of temple, Angkor Wat. (Eye Ubiquitous/Press Association Images)

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