Many were huge, as high as 150 meters, according to records. "If Chang'an reflects the duration of the Tang Dynasty, as it was used by the Tang as the capital for more than 200 years, then Luoyang represents the pinnacle of architectural achievement of that time," says Wang Kai, a local historian.

Today, the buildings are gone, but visitors can still see some of their unearthed foundations and tour replicas of some of the city's ancient components.

At the Dingdingmen Site Museum, the southern gate of Luoyang's outer city, visitors can see a re-creation of a Tang-era roadway featuring traces of wheel ruts, footprints and hoof prints. It is easy to imagine the bustle of trade along the ancient Silk Road, which linked Luoyang with Xiyu, a historical term used to describe modern-day Xinjiang Uygur autonomous region and Central Asia.

Because of this significance, the gate was named part of the UNESCO World Heritage site, "Silk Roads: the Routes Network of Chang'an-Tianshan Corridor", in 2014.