Exclusive: Laser technology reveals cities concealed under the earth which would have made up the worlds largest empire in 12th century
Archaeologists in Cambodia have found multiple, previously undocumented medieval cities not far from the ancient temples of Angkor Wat, the Guardian can reveal, in groundbreaking discoveries that promise to upend key assumptions about south-east Asias history.
The Australian archaeologist Dr Damian Evans, whose findings will be published in the Journal of Archaeological Science on Monday, will announce that cutting-edge airborne laser scanning technology has revealed multiple cities between 900 and 1,400 years old beneath the tropical forest floor, some of which rival the size of Cambodias capital, Phnom Penh.
Some experts believe that the recently analysed data captured in 2015 during the most extensive airborne study ever undertaken by an archaeological project, covering 734 sq miles (1,901 sq km) shows that the colossal, densely populated cities would have constituted the largest empire on earth by population at the time of its peak in the 12th century.
Evans said: We have entire cities discovered beneath the forest that no one knew were there at Preah Khan of Kompong Svay and, it turns out, we uncovered only a part of Mahendraparvata on Phnom Kulen [in the 2012 survey] this time we got the whole deal and its big, the size of Phnom Penh big.
A research fellow at Siem Reaps cole Franaise dExtrme-Orient (EFEO) and the architect of the Cambodian Archaeological Lidar Initiative (Cali), Evans will speak at the Royal Geographic Society in London about the findings on Monday.
Evans obtained European Research Council (ERC) funding for the project, based on the success of his first lidar (light detection and ranging) survey in Cambodia in 2012. That uncovered a complex urban landscape connecting medieval temple-cities, such as Beng Mealea and Koh Ker, to Angkor, and confirmed what archaeologists had long suspected, that there was a city beneath Mount Kulen. It was not until the results of the significantly larger 2015 survey were analysed that the size of the city was apparent.
That survey uncovered an array of discoveries, including elaborate water systems that were built hundreds of years before historians believed the technology existed. The findings are expected to challenge theories on how the Khmer empire developed, dominated the region, and declined around the 15th century, and the role of climate change and water management in that process.
Our coverage of the post-Angkorian capitals also provides some fascinating new insights on the collapse of Angkor, Evans said. Theres an idea that somehow the Thais invaded and everyone fled down south that didnt happen, there are no cities [revealed by the aerial survey] that they fled to. It calls into question the whole notion of an Angkorian collapse.
The Angkor temple ruins, which sprawl across the Unesco-protected Angkor archaeological park, are the countrys top tourist destination, with the main temple-city, Angkor Wat, appearing on the Cambodian national flag. Considered the most extensive urban settlement of pre-industrial times, and boasting a highly sophisticated water management system, Angkors supposed decline has long occupied archaeologists.
The new cities were found by firing lasers to the ground from a helicopter to produce extremely detailed imagery of the Earths surface. Evans said the airborne laser scanners had also identified large numbers of mysterious geometric patterns formed from earthen embankments, which could have been gardens.
Experts in the archaeological world agree these are the most significant archaeological discoveries in recent years.
Michael Coe, emeritus professor of anthropology at Yale University and one of the worlds pre-eminent archaeologists, specialises in Angkor and the Khmer civilisation.
I think that these airborne laser discoveries mark the greatest advance in the past 50 or even 100 years of our knowledge of Angkorian civilisation, he said from Long Islandin the US.
I saw Angkor for the first time in 1954, when I wondered at the magnificent temples, but there was nothing to tell us who had lived in the city, where they had lived, and how such an amazing culture was supported. To a visitor, Angkor was nothing but temples and rice paddies.