The Great Wall of China

 

The Great Wall is the largest man-made project in the world. 

The complete route is over 20,000 km, stretching from the east seaside to the west desert in northern China,winding up and down across mountains and plateaus like a dragon.

The Great Wall stretches across 15 northern Chinese provinces, municipalities and autonomous regions, from the Bohai Sea in the east to the Gobi Desert, 2,500 kilometers away in the west. There are 15 geographically important passes built along the route.

The Great Wall is not a single-structured wall, it includes beacon towers, barriers, barracks, garrison stations, and fortresses along the walls, together forming an integrated defense system.

The Great Wall developed from the disparate border fortifications and castles of individual Chinese kingdoms. 

For several centuries these kingdoms probably were as concerned with protection from their near neighbors as they were with the threat of barbarian invasions or raids.