Introduction to the Wangquanyu Great Wall: The Wangquanyu Great Wall was built from the second year of Yongle (1404) to the eighth year of Wanli (1580). During this period, the repairs were stopped, which took a total of 176 years. Although the overall length is only 2 kilometers, the altitude difference reaches 390 meters, which is greater than the 330-meter altitude difference between Beijing Jie and Caishikou Great Wall.