Lost cities of the Silk Road have been uncovered in the mountains of Uzbekistan.

However, using remote sensing technology, archaeologists have discovered at least two high-altitude cities that were situated at a key crossroads of trade routes.

One of them is Tugunbulak, a metropolis covering no less than 120 hectares, located at an altitude of over 2000 meters above sea level.

“The history of Central Asia is now changing thanks to this discovery,” said archaeologist Farhod Maksudov, a member of the research team.

The group believes that Tugunbulak and the smaller city of Tashbulak were bustling settlements from the 8th to the 11th centuries during the Middle Ages when the area was under the control of a powerful Turkic dynasty.

Only 3% of the world’s population currently lives at such heights. Lhasa in Tibet and Cusco in Peru are among the rare examples.

The discovery, led by Mr. Maksudov, director of the National Center for Archaeology of Uzbekistan, and Michael Frachetti, an archaeologist from Washington University in St. Louis, was made possible through the use of drones and a remote sensing tool called lidar, which employs reflected light to create three-dimensional maps of the environment.

Their study was published this week in the scientific journal Nature, and experts not involved in the research noted its significance for understanding the lifestyles of nomadic communities.

For the first time, the team discovered Tashbulak, the smaller of the two cities, in 2011 during an expedition in the mountains. They found burials, thousands of ceramic shards, and other signs that the area was inhabited.

Historical sources mention cities in this region, he said, but the team did not expect to find a medieval city covering 12 hectares at an altitude of about 2200 meters above sea level.

“We were amazed,” Mr. Frachetti told the BBC.

Even the ascent itself was challenging, he added, as they faced strong winds, storms, and logistical difficulties.

Four years later, a local ranger suggested the team explore another site near Tashbulak.

“This official said, ‘I think I have similar pottery in my yard.’ We went to his home… and discovered that his house was built on a medieval citadel. He was literally living on top of a vast city,” shared Mr. Frachetti.

The most challenging aspect of these discoveries was convincing the scientific community of the existence of these cities.

“We were telling people that we found this amazing site, and we faced skepticism: maybe it’s not that big, or it’s just a hill, or a castle... It was a major issue—how to document this city scientifically to truly show what it was,” said Mr. Frachetti.

In 2022, the team returned with a drone equipped with lidar, which helped peel away the top layer and reveal walls, watchtowers, intricate architectural elements, and other fortifications in Tugunbulak.

The researchers suggest that communities may have chosen Tugunbulak and Tashbulak to utilize the strong winds for igniting fires necessary for smelting iron ore, which the region was rich in. Preliminary excavations also uncovered production furnaces.

“Whoever had iron in their hands during the Middle Ages was very powerful,” noted Mr. Maksudov.

However, this could also have led to the decline of these communities, he added. Previously, this area was covered with dense juniper thickets that may have been cleared for iron production. “Due to frequent flooding and avalanches, the region became ecologically unstable,” he remarked.

Typically, scholars expected to find traces of settlements lower in the valleys, so “these findings are outstanding,” said Peter Frankopan, a professor of global history at Oxford University.
“What an incredible treasure showcasing deep connections across Asia, as well as ties to resource utilization over a thousand years ago,” he added.

High-altitude urban sites are “extremely rare” in the archaeological record, as communities face unique challenges in settling such locations, noted Zachary Sylvia, an archaeologist from Brown University.

The team's work represents a “huge contribution to the study of medieval urbanism in Central Asia,” he wrote in his comment to Nature.