Here is a look back as we went down the first part of the Wall. Pardon me as I play the part of the tour guide: The Great Wall of China, called Wan Li Chang Cheng (Long Wall of Ten Thousand Li) by the Chinese, measures about 6,200 miles from east to west, counting all its sections. The Wall dates back to the 5th century B.C. when the kingdoms of the Warring States Peroid (453 - 221 B.C.) built defensive ramparts against their enemies. The First Emperor of Unified China, Qin Shi Huang Di, fortified the barriers and, over a ten-year period, conscripted over 300,000 laborers to knit the walls together to protect the western barrier. The Great Wall was constantly repositioned along new routes as successive dynasties rose and fell and new sections extended the wall east to the Yellow Sea. The Mongols eventually broke through the Wall from the North in the 12th century to establish the Yuan Dynasty (A.D. 1271 - 1368), making Beijing their capitol city. Their successors were the emperors of the Ming Dynasty (A.D. 1368 - 1644) who set in motion the last phrase of wall building that created the Great Wall as we know it today.