Mimi Kirk is a contributing writer to CityLab covering education, youth, and aging. Her writing has also appeared in The Washington Post, Foreign Policy, and Smithsonian.
Satellite imagery and lasers are generating stunning new finds at sites like Angkor and Petra.
Earlier this month, archaeologists announced new finds at the site of Angkor in Cambodia—the medieval temple complex that includes the famed Angkor Wat. Researchers have discovered vast networks of cities surrounding the complex that would have been in their heyday in the 12th century. The largest of these cities may even rival the contemporary capital of Phnom Penh in size.
New methods in the field of “space archaeology”—which, just like it sounds, uses space-based technology to pinpoint undiscovered sites—are helping archaeologists make such spectacular finds. Tools such as satellite imagery, as well as sky-based methods like lasers, help show what lurks below the earth’s surface, even in areas with thick vegetation. In the case of Angkor, researchers used lasers attached to helicopters to map the ruins of subterranean infrastructure such as walls, roads, and canals.
Not long before the Angkor announcement, a new find came out of Petra, the rose-colored ruins of a city that flourished from around 300 B.C. through the 7th century A.D., in what is now Jordan. The archaeologist Sarah Parcak used high-res satellite imagery to locate a previously undiscovered monument—a huge platform containing a smaller platform with a building atop it—about half a mile south of the ancient city’s center.
Discoveries like these help to shed new light on ancient cities and cultures. At Angkor, the nature of the urban networks surrounding the temple complex suggest that Angkorians did not migrate south to a few particular locations in the 14th and 15th centuries, as was previously thought. The platforms at Petra provide an example of early building in the city and were likely a space for public political or religious displays.
Even for contemporary urban scholars, the case of Angkor is particularly instructive. Angkor had a dense core but a sprawling periphery—unusual for the era, but much like cities of today. Damian Evans, who leads the laser research in Angkor, told Next City that toward the end of the Angkor period, engineers were having trouble maintaining the city’s water system—which, due to the feast-or-famine nature of rainfall in the tropics, was key to its survival.
If something went wrong with a reservoir, for instance, the engineers would usually construct something bigger and better nearby. But eventually space ran out in central Angkor, and this occurred around the time of severe droughts and social turmoil. As a result, Evans explains, the infrastructure became a liability and hastened the city’s demise.
The lack of a long-term master plan for its urban space left Angkor unable to deal effectively with new social and environmental challenges. Evans notes that contemporary cities still face the same reality: a failure to plan adequately for growth can bring about chaotic expansion that lacks the infrastructure needed to sustain it, such as public transportation. In the face of climate change and extreme weather events, planning becomes even more essential.
Evans’ collaborator at Angkor, the University of Sydney professor Roland Fletcher, sums up the lesson for CityLab: “Since present-day megacities are trending to low density and drastically alter their environments, depend on massive infrastructure, and face severe climate issues, we would be wise to assess whether we confront the same risks as cities [like Angkor].”