Introduction
There are relics of the Silk Road. The Gansu Province Great Wall has the Mogao Caves. This section of the Great Wall was important to the military. It was built during the Qin, Han, Ming, and Warring State Periods. It stretches four thousand four hundred kilometers (two thousand seven hundred thirty-four miles) long. This section is built out of stones and bricks. It is built on solid earth, which is hard to break.
Dunhuang
This section is three hundred eighteen kilometers (eleven miles) west of the Jiayuguan Pass. This part of the wall is disappearing because of natural disasters and human destruction.
Jiayuguan Pass
The Jiayuguan Pass is six kilometers (four miles) away from Jiayuguan City. It was built during the Ming Dynasty. This section of the wall is eight acres (thirty-three thousand five hundred square miles). The construction of this part of the wall started in 1372. There was a legend that an official that oversaw the construction said not to waste even one brick. The wall finished with one extra brick. The extra brick is still there at the wall.
Juyan Fortress
It was built in 102 B.C.E. It goes along the Ejina River in Jinta County. The land on which it is is called Juyan. This section of the wall is three hundred fifty kilometers (two hundred seventeen miles) long. There are over thirty thousand wooden boards in the wall. It was built during the Han Dynasty. This section of the wall was discovered in 1930.
Overhanging
This part of the wall is eleven kilometers (seven miles) away from Jiayuguan City in Gansi Province. It was built in 1539. This section helped a lot defensively. It was built during the Ming Dynasty. This part of the wall is not visible when you are looking from west to east. Because of this, enemies thought that it was possible to enter China through the "emptiness" there. From a distance, this section looks like a dragon overhanging a slope. That is why this section of the wall is called Overhanging. It was built out of local gravel and yellow earth. There are three observation posts. It used to be one and a half kilometers (just under one mile) long. It is now seven hundred fifty-eight meters (eight hundred twenty yards) long. The section looks like the the Badaling section, which is near Beijing. It is around mountains and deserts.
Yangguan Pass
This section is sixty-nine kilometers (forty-three miles) southwest from Dunhuan City. It was built during the Han Dynasty. It was built to improve the front defense and develop the western defense. Emperor Wu commanded that this section be built.
Yumenguan Pass
This section was originally called Small Square City. It is one of the two important western passes. It was built during the Han Dynasty. This section is ninety kilometers (fifty-six miles) northwest of Dunhuang City. It was a crucial gateway to central China.