Ancient Walled City Unearthed in South China Beijing, 25 Feb (ONA) --- A walled city over 600 years old has been unearthed in Dongguan, south China's Guangdong Province, shedding light on the South China Sea coastal defense strategy at that time. Besides the two city wall sections about 100 meters long and 7.6 meters thick, urban facilities such as roads, drains, building bases and wells have also been discovered, as well as a large number of building ...