长城
Jiankou () is a section of the Great Wall of China. In English, 'Jiankou,' is translated to 'Arrow Nock' as the shape of the mountain resembles an arrow with the collapsed ridge opening up, reminiscent of an arrow nock. The wall is 20km long and located north of Beijing in the Huairou District. The Jiankou section of the Great Wall of China is located between the Mutianyu and the Moshikou sections of the Great Wall of China. It is built on a steep mountain ridge and a popular hike amongst visitors.