Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials,for protect the Chinese states and empires against the Raids and invasions of the various nomadic groups . Several walls were being built as early as the 7th century BC; These, later joined together and made bigger and stronger, are now collectively referred to as the Great Wall. Since then, the Great Wall has been rebuilt, maintained, and enhanced; The majority of the wall is from the Ming Dynasty (1368-1644). Great Wall of China is a barrier fortification in northern China running west-to-east 13,171 miles (21,196 km) from the Jiayuguan Pass (in the west) to the Hushan Mountains in Liaoning Province in the east, ending at the Bohai Gulf. It crosses eleven provinces Inner Mongolia and Ningxia. The Great Wall in the present day is almost completely the work of the Ming Dynasty (1368-1664 CE) who added the distinctive watchtowers and expanded the length and width of the wall. The now-famous national monument fell into decay following the Ming Dynasty, when the Qing Dynasty (1644-1912 CE) took power and expanded the border of China northwards, making the wall obsolete. Restoration and preservation efforts only seriously began in the 1980's CE, and the wall was declared a UNESCO World Heritage Site in 1987 CE. Construction of the wall began in the Qin Dynasty (221-206 BCE) under the First Emperor Shi Huangti and continued over hundreds of years throughout many different dynasties.
Other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or regulation of immigration and emigration. Furthermore, the defensive characteristics of the Great Wall were enhanced by the construction of watch towers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire, and the fact that the path of the Great Wall also served as a transportation corridor .
