This year's excavation work at Shangjing is expected to continue until October. Standing on the city's earthen outer boundary walls, which are still six to 10 meters above ground, he is optimistic about more discoveries.

"The city is a milestone of urban construction in ancient China, and many parts of history that have not been documented wait to be unearthed," he says.

In 2021, the Shangjing site was included in the list of the Top 100 Archaeological Findings in the Last 100 Years, which was revealed by the National Cultural Heritage Administration to honor the centennial of the birth of modern Chinese archaeology. Only three sites from Inner Mongolia made it to the list.

An emperor's legacy

Shortly after founding the Liao Dynasty, Khitan leader Yelyu Abaoji-an iconic figure in Chinese history-decided to build Shangjing as his national capital. Successors to his throne followed the nomadic lifestyle. Four more capitals were set up in the following decades, as where the emperor was where the capital was set. Beijing, for example, became the "southern capital" of Liao.

"Shangjing indisputably had the principal status while the other four cities were more like provisional capitals," Dong says.

Apart from vague descriptions in surviving historical documentation, the earthen mounds and walls, and scattered constructions of the Liao Dynasty in Baarin Left Banner, people mostly relied on imagination to connect the dots until the recent decades of archaeological work.