text: The Great Wall of China (Simplified Chinese:  Traditional Chinese: Pinyin: Wànlĭ Chángchéng; literally "10,000 Li¹ long wall") is a Chinese fortification built from 3rd century BC until the beginning of the 17th century, in order to protect the various dynasties from raids by Mongol, Turkic, and other nomadic tribes coming from areas in modern-day Mongolia and Manchuria. Several walls were built since the 3rd century BC, the most famous being the Great Wall built between 220 BC and 200 BC by the First Emperor, Qin Shi Huangdi, which was located much further north than the current Great Wall of China built during the Ming Dynasty, and little remains.\n\nThe Wall stretches over a formidable 6,352 km (3,948 miles), from Shanhai Pass on the Bohai Sea in the east, at the limit between China proper and Manchuria, to Lop Nur in the southeastern portion of Xinjiang Uygur Autonomous Region (refer to University of Washington: A. The Main Caravan Routes (b) The “Central Route” or “Middle Route.”)\n\nHISTORY \n\nA defensive wall on the northern border was built and maintained by several dynasties at different times in Chinese history. Its purpose, to defend the China mainland from nomadic Mongolians. There have been five major walls:\n\n208 BC (Qin Dynasty) \n1st century BC (Han Dynasty) \n7th century CE (Sui Dynasty) \n1138 - 1198 (Five Dynasties and Ten Kingdoms Period) \n1368 - 1640 (from Hongwu Emperor until Wanli Emperor of the Ming Dynasty) \nThe first major wall was built during the reign of the first Emperor of China, Qin Shi Huang. This wall was not constructed as a single endeavor, but was mostly the product of joining several regional walls built by the Warring States. The walls that were linked together at this time consisted of rammed earth with watch towers built at regular intervals. It was located much further north than the current Great Wall with its eastern end at modern day North Korea. Very little of this first wall remains - photos reveal a low, long mound.\n\nThe government ordered people to work on the wall, and workers were under perpetual danger of being attacked by brigands. Because many people died while building the wall, it has obtained the gruesome title, "longest cemetery on Earth" or "the long graveyard." Possibly as many as one million workers died building the wall, though the true numbers cannot be determined now.\n\nThe later long walls built by the Han, the Sui, and the Ten Kingdoms period were also built along the same design. They were made of rammed earth with multi-story watch towers built every few miles. These walls have also largely vanished into the surrounding landscape, eroded away by wind and rain.\n\nIn military terms, these walls were more frontier demarcations than defensive fortifications of worth. Certainly Chinese military strategy did not revolve around holding the wall, instead it was the cities themselves which were fortified.\n\nThe Great Wall which tourists visit today was built during the Ming Dynasty, starting around the year 1368 and lasting till around 1640. Work on the wall started as soon as the Ming took control of China but initially, walls were not the Ming's prefered response to raids out of the north. That attitude began to change in response to the Ming's inablilty to defeat the Oirat war leader Esen Taiji in the period 1449 to 1454. A huge Ming army with the Zhengtong Emperor at its head was anihilated in battle and the emperor himself held hostage in 1449.\n\nAppearently the real focus on wall building started as a result of Altan Khan's siege of Beijing which took place one hundred years later in 1550. The Ming, faced with the choice of trying to defeat the Mongols with direct military force, choose instead to build a massive defensive barrior to protect China. As a result, most of the Ming Great Wall was built in the period 1560 to 1640. This new wall was built on a grand scale with longer lasting materials (s