The famous temple complex of Angkor Wat, which draws so many tourists to Cambodia, is but one small structure in a new view of the region. Archaeologists have unearthed more sprawling remains of the once mighty Khmer empire, which ruled Southeast Asia between the ninth and the fifteenth centuries.
An international team led by Damian Evans, an archaeologist at the University of Sydney, Australia, flew a helicopter over 370 square kilometres of Khmer territory in April 2012. A lidar instrument on board bounced 200,000 laser pulses per second off the ground — so many that some laser blasts penetrated openings between leaves and could map out the forest floor below.
Lidar has been used to map other archaeological sites such as Angamuco in Mexico, Caracol in Belize, and what might be the famous lost White City in Honduras.
In Cambodia, the lidar revealed geometric structures like roads and canals connecting huge swaths of landscape. The survey suggests that the Khmer didn’t live in isolated urban clusters, but rather in a sort of low-density suburban sprawl dotted with nodes of greater population. The discovery suggests that Angkor’s urban centre — the heart of the vanished empire — may need to be redefined as covering 35 square kilometres rather than the 9 square kilometres usually thought, the team writes in an upcoming Proceedings of the National Academy of Sciences.
To the north and east of Angkor, Evans’s team found a second sprawling complex — which may be the city of Mahendraparvata, one of the empire’s first capitals. It is an ‘open city’, without a well-defined urban wall, that is surrounded by the massive canals and other water-moving features that the Khmer loved so much.
In fact, the Khmer’s very tendency to over-engineer their landscapes may have led to their ultimate doom. Whenever drought killed rice and other crops, the Khmer simply moved elsewhere and built even larger canals — stretching beyond the landscape’s sustainability. Decades-long droughts in the fourteenth and fifteenth centuries finally helped to do the civilization in.