According to RIA Novosti citing the Sina.com portal, 6,260 kilometers of the wall are made of brickwork, 2,232.5 kilometers are of natural mountain terrain. Finally, about 360 kilometers are not a wall at all but water-filled ditches.
Notably, until recently, dictionaries stated that the total length of the Great Wall of China was between 4,000 and 6,700 kilometers.
Construction of the Great Wall began in the 3rd century BC. Nowadays, mainly sections of the wall built 600 years ago during the Ming Dynasty have survived. Initially, the wall was intended to protect China's territory from nomadic invasions. Today it is recognized as one of the few man-made structures on Earth visible to the naked eye from space.