Starting from Shanhaiguan in the east and ending at Jiayuguan in the west, the Great Wall has an approximate length of 6,7O0 kilometres. The Great Wall twists, and runs mostly in mountains or in the deserts or turns up the mountains and down valleys. Without any use of machinery at all, it was really an unimaginably difficult job at that time, especially some of the stone blocks were as big as more than 1,000 kilograms a piece in weight. The Great Wall was a gigantic defensive project used in ancient times as early as in the 7th ... (more)