The Great Wall of China was built over 2221 years ago.
It was build out of wood, stone, bricks, tampered earth and other materials
Empour Qin Shi Huang was the one who made the walls join up.
It was build to defend China empires against raiders and invasioners.
Other purpose were to create border control 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 wall was from Dandong, in the east and Lop Lake, in the west.
That measures 8850Km
