<P> Other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration . Furthermore, the defensive characteristics of the Great Wall were enhanced by the construction of watch towers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire, and the fact that the path of the Great Wall also served as a transportation corridor . </P> <P> The Great Wall stretches from Dandong in the east to Lop Lake in the west, along an arc that roughly delineates the southern edge of Inner Mongolia . A comprehensive archaeological survey, using advanced technologies, has concluded that the Ming walls measure 8,850 km (5,500 mi). This is made up of 6,259 km (3,889 mi) sections of actual wall, 359 km (223 mi) of trenches and 2,232 km (1,387 mi) of natural defensive barriers such as hills and rivers . Another archaeological survey found that the entire wall with all of its branches measure out to be 21,196 km (13,171 mi). Today, the Great Wall is generally recognized as one of the most impressive architectural feats in history . </P> <P> The collection of fortifications known as the Great Wall of China has historically had a number of different names in both Chinese and English . </P> <P> In Chinese histories, the term "Long Wall (s)" (長城, changcheng) appears in Sima Qian's Records of the Grand Historian, where it referred to both the separate great walls built between and north of the Warring States and to the more unified construction of the First Emperor . The Chinese character 城 is a phono - semantic compound of the "place" or "earth" radical 土 and 成, whose Old Chinese pronunciation has been reconstructed as * deŋ . It originally referred to the rampart which surrounded traditional Chinese cities and was used by extension for these walls around their respective states; today, however, it is much more often the Chinese word for "city". </P>

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