The construction of the great wall of China

 .The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials, generally built along an east-to-west line across the historical northern borders of China to protect the Chinese states and empires against the raids and invasions of the various nomadic groups of the Eurasian Steppe. Several walls were being built as early as the 7th century BC; these, later joined together and made bigger, stronger, and unified are now collectively referred to as the Great Wall. Especially famous is the wall built between 220–206 BC by the first Emperor of China, Qin Shi Huang. Little of that wall remains. Since then, the Great Wall has on and off been rebuilt, maintained, and enhanced; the majority of the existing wall is from the Ming Dynasty (1368–1644).

The Great Wall stretches from Dandong in the east to Lop Lake in the west, along an arc that roughly delineates the southern edge of Inner Mongolia. A comprehensive archaeological survey, using advanced technologies, has concluded that the Great Wall has a total length of 21,196 km (13,171 mi). Another archaeological survey found that the entire wall with all of its branches measures out to be 21,196 km (13,170 mi).

The Great Wall of China is one of the world's most famous landmarks, and it is also the longest wall in the world. It is considered to be one of the most impressive architectural feats in human history, and it has become a symbol of China's ancient civilization. It is also