The Great Wall of China (Chinese: 萬里長城; pinyin: Wànlǐ Chángchéng) is the collective name of a series of fortification systems generally built across the historical northern borders of China to protect and consolidate territories of Chinese states and empires against various nomadic groups of the steppe and their polities. This collection of fortifications known as the Great Wall of China.The Great Wall of China, one of the greatest wonders of the world, was listed as a World Heritage by UNESCO in 1987. Just like a gigantic dragon, it winds up and down across deserts, grasslands, mountains and plateaus, stretching approximately 21196 kilometers from east to west of China with a history of about 2700 years. It took more than 2,500 years to finish the construction of the Great Wall. The wall was not built in a single time period, but combined effort of many states and dynasties in history