Shitaizi Mountain City,a national key cultural relics, was built in the early Tang Dynasty, more than 1,500 years ago. It is one of the few and well-preserved cultural sites of the Goguryeo period in Northeast Asia. It is about 430 meters from north to south, about 286 meters from east to west, with a circumference of about 1384 meters. Built according to the shape of the mountain, it is a "closed mountain city"with an area of about 60,000 square meters. In 2006, it was selected as one of the top ten new archaeological discoveries in China. Well-preserved city walls, defense platforms, large reservoirs, city gates, commanding platforms, dams and residential sites were excavated, with more than 1,000 pieces of relics unearthed. This mountain city is an outstanding representative of Goguryeo stone-built towns that have been excavated in China. It is of great significance to the study of the late Goguryeo history and its architecture.