The Great Wall of China is a series of fortifications built in the 15th century to protect the Chinese Empire from invading forces. Spanning over 21,000 km, it is the longest man-made structure in the world and a UNESCO World Heritage Site. It is an iconic symbol of
From Wikipedia
The Great Wall of China is a series of fortifications in China. They were built across the historical northern borders of ancient Chinese states and Imperial China as protection against various nomadic groups from the Eurasian Steppe. The first walls date to the 7th century BC; these were joined together in the Qin dynasty. Successive dynasties expanded the wall system; the best-known sections were built by the Ming dynasty (1368–1644).