As archaeologists dug, different soil layers were revealed, which documented the chronology of the city's change and evolution from the Western Zhou Dynasty (c.11th century-771 BC), to the Ming and Qing (1644-1911) dynasties, according to Chen.

Among the unearthed pottery, some have patterns or characteristics found in the Erligang culture in the Shang Dynasty (c.16th century-11th century BC), the 3,300-year-old Yinxu Ruins and the Maqiao culture in Taihu Lake region, He Yun'ao, a professor of history at Nanjing University, told the seminar.

"Due to its geographic location, Nanjing has played an important role in the development of the Chinese civilization. Starting from the ancient city of Changgan, it has become a place for the inheritance and continuation of the Chinese civilization and a hub for the convergence and dissemination of the northern and southern cultures for more than 3,000 years," He says.

The excavation began in 2017 after the Nanjing government launched predevelopment work for urban planning in the city's southern area, which is located in the Changganli Ancient City relics site. This is one of Nanjing's key protection zones for subterranean heritage. In 2020, archaeologists conducted a proactive archaeological survey of the site.

Wang suggested developing the Changgan ancient city site into a relics park and a museum to let the public be better involved in sharing the archaeological discoveries and the latest excavation process.

Wang Kaihao and Cang Wei contributed to this story.