Introduction to the ancient city wall: The Pingyao City Wall was built as a rammed earth city wall during the period of King Xuan of the Western Zhou Dynasty (827 BC to 782 BC). It was rebuilt in the third year of Hongwu in the Ming Dynasty (1370), and the original "nine miles and eighteen steps" was expanded to "twelve miles, eight and four cents" (6.4 kilometers), and the rammed earth city wall was transformed into a masonry wall. It was repaired twenty-five times in the Ming and Qing dynasties. The city wall is square in plan, with a circumference of 6162.7 meters and a height of 10 meters. The battlements are 2 meters high and the top is 3-5 meters wide. There are 77 drainage channels built in brick walls. A 2-meter-high creneled wall (also known as a horse-blocking wall) was built outside the top of the wall. Taking the number of Confucius disciples and sages, there were 3,000 crenellations, 72 watchtowers, and a parapet built inside. There are four corner towers, a general tower on the east wall, and Kuixing Tower and Wenchang Pavilion on the top of the southeast corner.