Zhangbi Ancient Castle.

Zhangbi Ancient Castle is a miniature ancient castle in Jiezhou City, Shanxi Province, China, with rich historical and cultural connotations and unique architectural style. The ancient castle was formed during the Northern Dynasty and the Sixteen Kingdoms, and gradually formed a five-level military defense system with "above-ground castle, underground tunnel" as the main structure through three stages: fortification, military town, and defensive village. The ancient castle is 374 meters long from east to west, 244 meters wide from north to south, and covers an area of 120,000 square meters. The castle has a rich and diverse culture, including ancient tunnels, Khan Temple, Kongwangxing Temple, Liuli Monument, ancient stage and many other cultural relics. The ancient castle has a five-level ancient military defense system with castle gates, alley gates, secondary alley gates, courtyard gates, and tunnels. The tunnel is 20 meters deep from the ground, divided into upper, middle and lower three layers, with a total length of more than 10,000 meters, and is a typical representative of the northern fortress in China with high historical, artistic and scientific value.