Great Wall of China
Huairou Beijing China
2014

Great Wall of China in Huairou, Beijing
In Huairou, a suburban district 50 kilometers (31 miles) north from the downtown of Beijing, you can enjoy some of the most essential parts of the Great Wall of China, like the Mutianyu Great Wall, Jiankou Great Wall, Huanghuacheng Great Wall, and Xiangshuihu Great Wall. With easy access and incomparable sceneries, the Great Wall of China Huairou has won great popularity among tourists.

Mutianyu Great Wall
Among all the Great Wall of China Huairou, Mutianyu is the most famous. It is the existing longest section of the Great Wall. Looking from a distance, the awe-inspiring Mutianyu resembles a giant dragon winding on the mountain ridges. The watchtowers are densely distributed and you can see crenels every a few steps on both sides of the wall. In the Zhengguan Terrace, three hollow watchtowers are set next to each other, which is rarely seen elsewhere. With such special design, this is a perfect lookout tower. Soldiers can clearly see enemies no matter which direction they came from.

https://en.wikipedia.org/wiki/Great_Wall_of_China

The Great Wall of China is a series of fortifications that were built across the historical northern borders of ancient Chinese states and Imperial China as protection against various nomadic groups from the Eurasian Steppe.

Today, the defensive system of the Great Wall is generally recognized as one of the most impressive architectural feats in history.