The Gubeikou Great Wall Gubeikou Great Wall is located 128 kilometers (80 miles) southeast of Beijing winding on the ridges from east to west with a total length of 21,000 meters (13 miles). It comprises of four stretches Panlongshan Section, Wohushan Section, Jinshanling Section and Simatai Section of which the Simatai Section is the most difficult to climb. The Gubeikou Great Wall was constructed in 1368 for defending against invasion of the northern tribes and was further expanded in 1567, which is this section now. Gubeikou was a strategic pass of the Great Wall in olden times, for Panlong Mountain and Wohu Mountain are linked by it, whilst the Chao River runs across Gubeikou Great Wall, providing a vital access to Inner Mongolia and northeast of China. Therefore wars for controlling this point never stopped until the ruling Qing Dynasty (1644-1911) settled its capital in Beijing. Even now you can still view some traces of the battles on some of the broken bricks and stones and many cultural relics including arrows, bamboo guns, stone mills and knives can be found here. Therefore because of their great military importance, defensive projects of this kind appeared as early as 555 AD, which known as the earliest section of Great Wall. However, because they were made of stamped earth you can hardly find any traces of the site after thousands of years. The wall we see today in Gubeikou was built in Ming Dynasty (1368-1644). The beacon towers on the Gubeikou Great Wall are of a great number and the distance between each is an average of 30 meters (98 feet). There are various in styles of Towers, some quite different from each other, of which the two towers erected side by side on cliffs separated by the Chao River are called 'Sister Towers'. You can also have a look at the 'Watergate Pass' bridged over the river.