Yanzhou Cheng

Baiyan city walls by Rincewind42. Sourced via Flickr under Creative Commons Attribution License.

This is a well preserved ancient city with buildings dating back to the Tang Dynasty over 1200 years ago. It was built by the Goguryo people as was the scene of a major battle between the Goguryo and the Tang emperor. It is rare because the ancient structures are well preserved with little later construction obscuring the older parts and so has received provincial level protection.

This city fortress follows the most common form of Goguryeo fortresses. It was one made in the shape of the moon, located beside a river. Ditches and ground walls between the shores formed an extra defense line. The walls were made from huge stone blocks fixed with clay, and even Chinese artillery had difficulty to break through them. Walls were surrounded by a ditch to prevent an underground attack, and equipped with guard towers. All fortresses had sources of water and enough equipment for a protracted siege.