In c. 220 B.C., under Qin Shi Huang, sections of earlier fortifications were joined together to form a united defence system against invasions from the north. Construction continued up to the Ming dynasty (1368–1644), when the Great Wall became the world’s largest military structure.
Unesco WHS list ref: 438
I visited a tiny part of this site during a work visit to China
From my collection
Cards to swap
I have many more spare cards of the Great Wall – scans will be added soon.