What lies beneath

Be prepared to sweat. Exploring the world’s largest religious complex in the Cambodian jungle is not for those who can’t take the heat. The sheer size of the gigantic edifices of Angkor Wat and the distances between them means long treks, in 40-degree heat and humidity as if in a sauna.

But then, what you get to see is stunningly unique. There are the monument-sized sandstone buildings, delicate carved bas-reliefs, and the strangler figs, huge snake-like plants creeping up the walls and buildings as if to swallow them up. Like in some enchanted forest.

It is almost impossible to believe that more than 800 years ago, in the heyday of the Khmer culture, hundreds of thousands of people lived in this merciless jungle setting.

But what archaeologist Damian Evans has now uncovered with the help of an airborne laser measurement technology called Lidar (light detection and ranging) explodes everything that was known heretofore.

It was known, for example, that there used to be a sophisticated irrigation system in the settlements around Angkor Wat. But the sheer size of the system is much greater than realised.

“It is truly astonishing,” says Charles Higham of Otago University in New Zealand and one of the leading archaeologists in Southeast Asia. 

“These findings have enormously enriched our knowledge about the Angkor cultural landscape. Now we know what had lain between the temples and the surrounding irrigation ditches, and how the roads were laid out, where the canals and embankments ran. All this had until now been a puzzle.”

Where only stone temples are now observable to the naked eye, Evans’ laser measurements suddenly unveiled all the surrounding structures – ditches, ponds, mounds. “It is as if, in a European city, you had known only the locations of the churches, and then suddenly you have an entire city map (of the streets),” he writes.

Nothing is left of the Angkor Wat residential areas. The houses were of wood, mud and straw and have long ago decayed away.

The first measurements taken in 2012 were already spectacular. But now Evans has discovered new details in a far larger area.

“It has conventionally been believed that ‘all roads lead directly to Angkor’,” he writes. But now new evidence of another highway linking the sites identified as Preah Khan and Sambor Prei Kuk points to the possibility of “the first-known provincial ‘loop’ in the highway system.”

Archaeologist Martin Polkinghorne of Flinders University in Australia notes that “until now our knowledge of the history was based on interpretations of stone inscriptions that Angkor’s elites left behind. With these measurements our knowledge is being greatly enhanced.”

One major historical question is Angkor Wat’s downfall. Until now, one theory had been that people fled south, fearing an invasion from what is now Thailand. “But the new data suggests that there never were so many people living there as in Angkor,” Polkinghorne says,.

“Now we can begin to date more precisely the end of the Angkor empire.”

The city layout discovered by Evans resembles more a modern US city with its straight roads. There is no doubt that it was a mega-city, larger than today’s Berlin and the seat of possibly the planet’s largest empire of the 12th and 13th centuries. 

“Yes, many things must now be reconsidered,” comments Andreas Reinecke, an archaeology expert on cultures outside of Europe. He pointed out that the measurements do clearly outline previously hidden structures, but not their ages.

“There will certainly be many exciting years of field research ahead until we know more precisely about dating the structures and about the reasons for the very differing degrees of the destruction of the complex.”

The Angkor empire with its urban structure appears not only very modern, but also, in Evans’ view, offers lessons for today’s society.

The large-scale deforestation, the massive incursions in the ecology with complex irrigation canals and a city that kept growing larger and larger were factors that, in the end, were unsustainable.

These were the likely factors contributing to its downfall when climate changes brought sustained periods of drought in the late 14th and early 15th centuries.