Although the construction of the Mutianyu Great Wall began in the Northern Qi Dynasty, those walls were mostly just ruins. The true construction of the Mutianyu Great Wall began during the Ming Dynasty, when General Xu Da, the founding general of the Ming Dynasty, decided to build this section of the wall during his expedition against the Northern Yuan Dynasty in 1368. To ensure the safety of Beijing, Xu Da chose to rebuild the wall in the Yanshan Mountains, and the Mutianyu Pass was a key project for the Great Wall. However, due to financial difficulties during the early years of the Ming Dynasty, only the basic infrastructure was completed. Over 200 years later, General Qi Jiguang continued to improve the design of the Great Wall. During his tenure, more than 1,000 enemy towers were built along the Beijing Great Wall, and 20 enemy towers were built over just 5 kilometers at Mutianyu. Overall, the Mutianyu Great Wall has a history of more than 600 years since its construction began in the early Ming Dynasty in 1368.