Following the Afghan Silk Road with satellites

Using high-tech tools, archaeologist Emily Boak has discovered a wealth of Afghan structures.

The 23-year-old researcher at the University of Chicago has uncovered 100 previously unrecorded caravanserais — giant, protected stopover points for merchants traveling along the Silk Road. Using a $2 million award from the U.S. Department of State, Boak, as part of the Afghan Heritage Mapping Partnership, has had access to commercial satellite imagery, aerial data from the U.S. Army Corps of Engineers and even spy satellite data from the 1960s and 1970s.

In Afghanistan, a country where archaeological work has been almost off-limits since the 1979 Soviet invasion, these aerial and satellite images are unlocking mysteries of cultural heritage and helping researchers to map thousands of previously undiscovered sites.

After spending time with the images, researchers have just started finding the caravanserai sites, according to Boak.

The Silk Road was an ancient network of trade routes that connected a vast area of the Indo-Pacific: Products, craftspeople and knowledge from East Asia and India traveled through the Middle East to Europe, and vice versa. The caravanserais were rectangular structures built around a massive courtyard — often roughly the size of an American football field — where large groups of merchants and camels could rest. Boak’s team has found caravanserais that were in use from the 1500s to about 1700.

Satellite image of rectangular caravan stop (U.S. Army/University of Chicago)
The courtyard of this site near Herat, Afghanistan, could hold 300 camels. (U.S. Army/University of Chicago)

“People were carrying everything from silk to gems, spices, wood from India, porcelain from China,” Boak said. “And then you have the less exotic cargo, like dried fish.” Caravanserais also served as important social spaces. “If you needed information about a specific traveler from a specific country, or if you were looking for news from far away, you’d often go to the nearby caravanserai,” Boak said.

“It was the system of hospitality that allowed all of this trade to happen.”

From the air, the routes and canals of lost empires weave a rich tapestry. “You start to get a sense less of dots on a map and more how this whole system connects,” Boak said.

The Afghan Heritage Mapping Project partners with the National Museum of Afghanistan and Kabul Polytechnic University to preserve Afghanistan’s cultural heritage and train the next generation of Afghan archeology students.

Boak says satellite mapping has enabled her team to triple the country’s published archaeological sites. But there’s so much more to discover. “We’ve covered just a fraction of Afghanistan,” Boak said. “There are thousands more sites to be recorded.”

Did you know that you can use satellite imagery to help archeologists protect ancient sites? Check out GlobalXplorer, a platform from space archaeologist Sarah Parcak, which lets you survey sites and stop looters.