Great Wall is also known as Ten Thousand Li Great Wall as it stretches for about 4,500 miles (7,300 km) east to west from Shanhaiguan Pass near Bo Hai (Gulf of Bohai) to Jiayuguan Pass (in Gansu province) traversing Liaoning, Hebei, Tianjin, Beijing, Shanxi, Inner Mongolia, Shaanxi, Ningxia and Gansu. (Note: Li is a Chinese unit for length; ten thousand Li equals five thousand kilometers).
The earliest great walls appeared in the Spring and Autumn Period and Warring States Period (770 BC - 221 BC), when each state built beacon towers and connected them with walls to prevent invaders. In the following two thousand years, the Great Walls were renovated and rebuilt many times, especially in the Ming Dynasty (1368 - 1644), so the Great Walls we can see today are mostly Ming Dynasty Great Walls. But some earlier sections still can be found, such as the Han Dynasty Great Wall in Dunhuang, Gansu Province.
Each section of Great Wall has its own feature due to the distinct geography and climate conditions. For example, the Great Walls in Gansu Province and Shaanxi Province were built of loess, which is the local specialty in the Loess Plateau; the Jiumenkou Great Wall in Liaoning Province stretches along the Jiujiang River and strides over the river; the Badaling Great Wall in Beijing roiling along the mountain ranges to make the mountains a natural barrier.
Beijing Great Wall: Badaling Great Wall, Mutianyu Great Wall, Simatai Great Wall, Jinshanling Great Wall, Juyongguan Pass, Jiankou, Huanghuacheng, Gubeikou, Shuiguan
Gansu Great Wall: Jiayuguan Pass, Yumenguan Pass, Yangguan Pass, Dunhuang Great Wall, Overhanging Great Wall
Hebei Great Wall: Shanhaiguan Pass, First Pass under Heaven, Laolongtou, Temple of Meng Jiangnü, Xifengkou Gateway, Zijingguan Pass
Inner Mongolia Great Wall
Liaoning Great Wall: Hushan, Jiumenkou
Ningxia Great Wall
Shaanxi Great Wall: Zhenbeitai Tower, Yulin Great Wall
Shanxi Great Wall: Yanmenguan Pass, Niangziguan Pass, Pianguan Pass
Tianjin Great Wall: Huangyaguan Pass, Taipingzhai
