The renowned 'Martial City' of the northern frontier, the once flourishing 'Commercial Port' Zhangjiakou Fort

Zhangjiakou Fort, also known as Baozili, was first built in the fourth year of the Xuande period of the Ming Dynasty (1429). Initially a military fort due to its strategic location, it was thus honored as the 'Martial City' of the northern frontier. Later, due to the border-opening policy, it became a place for Mongolian-Han mutual markets and an important node on the Zhangku Trade Route, renowned as a northern land commercial port due to its significant role as a trade distribution center. The buildings inside the fort are mainly courtyard houses, with more than 700 cultural relics and historical sites still existing, including 93 key courtyards, earning it the title of 'Museum of Ming and Qing Architecture.' The Wenchang Pavilion, located at the center of the fort, was built in the forty-sixth year of the Wanli period of the Ming Dynasty (1618). The entire structure is divided into two parts: the upper part is a pavilion temple, and the lower part is a cross-arched passage made of brick and stone, connecting the four main streets in the east, west, south, and north, hence it is also known as the 'Four-Gate Passage.' The four gates of the Wenchang Pavilion each have a name: the south gate is called 'Wenchang Pavilion,' the north gate 'Bell Tower,' the east gate 'Drum Tower,' and the west gate 'Mountain Tower.' The center of the dome is inlaid with a stone slab of the Taoist Bagua diagram, carved with the ancient Chinese Heavenly Stems and Earthly Branches, and the stone slab is surrounded by inverted lotus flower thrones, subtly implying Buddhist culture. In addition to the Wenchang Pavilion, the fort also houses many other historical sites such as the Luncai Academy and the General Ding's Mansion. Today, it has become a popular place to explore the 'origin' and 'roots' of Zhangjiakou.