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.
Fortifications are military constructions or buildings designed for the defense of territories in warfare, and also used to solidify rule in a region during peace time.
The Eurasian Steppe, also called the Great Steppe or the steppes, is the vast steppe ecoregion of Eurasia in the temperate grasslands, savannas, and shrublands biome.
National Geographic - The Great Wall of China - Documentary by ChannelM
Several walls were being built as early as the 7th century BCE; these, later joined together and made bigger and stronger, are now collectively referred to as the Great Wall.
National Geographic Great Wall Of China by Neha Gupta
Especially famous is the wall built 220–206 BCE by Qin Shi Huang, the first Emperor of China.
Qin Shi Huang or Qin Shi Huangdi, meaning the First Emperor of Qin, was the founder of the Qin dynasty and the first emperor of China.
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.
The Ming dynasty was the ruling dynasty of China—then known as the Empire of the Great Ming—for 276 years following the collapse of the Mongol-led Yuan dynasty.
Other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration.
The Silk Road or Silk Route was an ancient network of trade routes that for centuries were central to cultural interaction through regions of the Asian continent connecting the East and West from China to the Mediterranean Sea.
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.
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.
Inner Mongolia, officially Inner Mongolia Autonomous Region or Nei Mongol Autonomous Region, is an autonomous region of the People's Republic of China, located in the north of the country, containing most of China's border with Mongolia and a small section of the border with Russia.
Lop Nur or Lop Nor is a former salt lake in China, now largely dried-up, located between the Taklamakan and Kumtag deserts in the southeastern portion of Xinjiang Uygur Autonomous Region in the People's Republic of China.
Dandong, previously known as Andong, is a prefecture-level city in southeastern Liaoning province, People's Republic of China.
A comprehensive archaeological survey, using advanced technologies, has concluded that the Ming walls measure 8,850 km.
This is made up of 6,259 km sections of actual wall, 359 km of trenches and 2,232 km of natural defensive barriers such as hills and rivers.
Another archaeological survey found that the entire wall with all of its branches measure out to be 21,196 km.