China's Great Wall part I - The Mongol Invasion (full documentary)

Purposes of the Great Wall of China have included border controls, allowing the imposition of duties on goods transported along the Silk Road, [caption id="attachment_719" align="alignnone" width="300"] Great Wall,China,Mongol Invasion,Documentary,Silk Road,China Wall[/caption] regulation or encouragement of trade and the control of immigration and emigration.archaeological survey found that the entire wall with all of its branches measure out to be 21,196 km (13,171 mi).Hope you will like this Himalaya Documentary