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Lost for centuries, two cities lay buried, almost three miles apart, beneath grassy meadows in the mountains of Uzbekistan. Now, for the first time, archaeologists have mapped these intriguing highland strongholds in the country's southeast - once an important crossroads of ancient silk trade routes - which were inexplicably abandoned.
Using drone-powered LiDAR (light detection and ranging equipment) that can find structures obscured by vegetation, researchers have captured images that reveal two unexpectedly large-scale urban settlements, dotted with watchtowers, fortresses, complex buildings, squares and paths where tens of thousands of people can go to. called home.
Discovering what would have been bustling medieval cities at a dizzying height of more than 2,000 meters (6,562 feet) above sea level was surprising, said anthropologist Michael Frachetti, lead author of the new study published Wednesday in the journal Nature.
Life in the two settlements would have been tough, especially during the winter months. "This is the land of the nomads, the land of the pastoralists. As far as most people are concerned, it's a periphery," said Frachetti, a professor of archeology in the Spatial Analysis, Interpretation and Exploration laboratory at Washington University in St. Louis.
Today, according to the research, only 3% of the world's population lives at or above such high altitudes, mainly on the Tibetan Plateau and in the Andes. Ancient settlements in the highlands, such as Machu Picchu in Peru, are considered anomalies given the harshness of life at high altitude, the study said.
"It's a very different environment up there," Frachetti said of the newly discovered settlements on the Silk Road. "It's already winter there. It's freezing. We get snow in the summer."
The archaeological team has begun preliminary excavations at the two sites to unravel who exactly founded the enigmatic lost cities - and why.
High mountain towns of nomads?
The mountains and steppes of Central Asia have been home to powerful nomadic groups for thousands of years. These mounted nomads built empires and focused their lives on herding animals such as sheep, goats and cattle since the Bronze Age.
However, the newly discovered highland cities were too large to simply be trading posts or stops on the Silk Road, Frachetti and his colleagues believe. More likely, they reasoned in the study, the urban settlements were built to exploit the abundant iron ore found underground in the region. The team hopes that excavations will reveal who founded and inhabited the cities.
"The entire region has a highly valued commodity of the time, iron, and it is also dense with juniper forests, which would have provided fuel (for smelting)," Frachetti said.
Although the region is not suitable for agriculture, he believes the surrounding land would have sustained the town's residents by supporting grazing herds as part of the pastoral lifestyle that had long existed there. Furthermore, the mountainous terrain would also have provided an effective defensive position.
Together with his Uzbek colleague and co-author Farhod Maksudov, researcher and director of the National Center of Archeology of the Academy of Sciences of the Republic of Uzbekistan, Frachetti first came across one of the settlements in 2011 during an archaeological survey of the region . .
"Our goal at the time was actually to study the prehistory of these mountain areas in relation to the development of nomadic pastoralism," he said.
"During that work we came across the smaller of the two towns, Tashbulak, and it was quite a thrill to find a town in the highlands," he said.
Laser mapping reveals archaeological wonders
Frachetti and his colleagues found the second and largest of the two towns, Tugunbulak, in 2015 after a local forester mentioned similar shapes to those in Tashbulak in the landscape where he lived.
'We got there and in the middle of his backyard is a medieval citadel. He just didn't know.
We go up the hill and look outside, and we can see hills and pyramidal (shapes) everywhere, and we think, oh my god, this place is huge.
The team mapped the two cities in 2022, making 22 flights with a drone equipped with LiDAR. According to the study, this was the first time researchers used the technology in the region.
A LiDAR sensor tracks how long it takes for each laser pulse to return and uses that information to create a three-dimensional map of the environment below. The technique has revolutionized the study of human history and culture and has been especially useful in discovering archaeological sites in the Amazon rainforest and Mayan sites in Central America.
During the heyday of the medieval Silk Road, cities emerged and others flourished, says Zachary Silvia, a postdoctoral research associate at the Joukowsky Institute for Archeology and the Ancient World at Brown University in Rhode Island. But better-known cities along the route, such as Samarkand in Uzbekistan and Kashgar in China, were located in vast agricultural oases.
"High-altitude urban sites are extremely rare in the archaeological record due to a unique set of landscape challenges and technological demands that must be overcome before humans can form large communities in mountainous areas," wrote Silvia, who was not involved in the research. in a commentary published alongside the study.
"The discovery of Tashbulak and Tugunbulak forces us to reconsider ideas about the optimal location for founding a city."
The study, based on the LiDAR data, found that Tugunbulak covered approximately 1.2 square kilometers (120 hectares) and showed evidence of more than 300 unique structures, ranging in size from 30 to 4,300 square meters (323 to 46,285 sq. foot).
Tashbulak, meanwhile, covered 0.12 to 0.15 square kilometers (12 to 15 hectares) and although smaller, included a citadel made of a raised hill surrounded by dense architecture and walled fortifications made of rammed earth. The research team found at least 98 visible homes, similar in shape and size to those in Tugunbulak.
The researchers believe Tashbulak was inhabited between the sixth and 11th centuries, while Tugunbulak was active from the eighth to the 11th century, he said.
It is not clear why the settlements were abandoned. "Those stories will become clearer as we delve deeper into the archaeology," Frachetti said. There are no signs they have been razed, burned or attacked, he added, but it is a subject of active study.
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