The Great Wall of China is one of the great wonders of the word. It stretched 4,500 miles, from the mountains of Korea to the Gobi Desert; it was first built to protect an ancient Chinese empire from enemies. .
The oldest section of the Great Wall was begun in 221 B.C., Qin Shi Huang, restored the ruins of older walls and linked them with new construction to create 3,000-mile-long fortification meant to protect China's northern frontiers against attack by nomads. Qin Shi Haung was no benevolent ruler looking out for his people. His followers believed that people were inherently evil and needed to live by a strict set of rules. The emperor made harsh decisions and sentenced thousands of intellectuals to years of forced labor on the Great Wall. As the wall inched across the Chinese wilderness, its builders were forced to rely upon local materials. Much of the Qin wall was built with dry-laid native stone, but where scarce, engineers built the wall from layers of compacted earth. The tamped-earth process began with a simple wooden frame. Workers filled the frame with loose earth, which was placed into a compact layer 4 inches thick. The process was repeated layer upon layer, and the wall slowly rose 4 inches at a time. After the downfall of the Qin Empire, China was one land.
Even Qin Shi Huang's Great Wall started to fall apart, suffering from years of neglect.
The other group that also builds the great Wall was the Han in 206 B.C. They came to power after the downfall of the Qin. They first laid a bed of red willow reeds and twigs at the bottom of a wooden frame, then they filled the frame with a mixture had thoroughly dried, the wooden frame was removed, leaving behind a solid slab of tamped earth, strengthened by the willow reeds just as modern concrete is reinforced by steel rods. The Han also added beacon towers to the Wall, spaced 15 to 30 miles apart.
The greatest of all wall builders were the Ming; whose astounding accomplishments dwarfed what had been doe earlier by the Qin and the Han.