<P> As China opened up in the 1980s, reformist leader Deng Xiaoping initiated the "Love our China and restore our Great Wall" campaign (爱 我 中华, 修 我 长城) to repair and preserve the Great Wall . The Great Wall was designated as a UNESCO World Heritage Site in 1987 . However, while tourism boomed over the years, slipshod restoration methods have left sections of the Great Wall near Beijing "looking like a Hollywood set" in the words of the National Geographic News . The less prominent stretches of the Great Wall did not get as much attention . In 2002 the New York - based World Monuments Fund put the Great Wall on its list of the World's 100 Most Endangered Sites . In 2003 the Chinese government began to enact laws to protect the Great Wall . </P> <P> In China, one of the first individuals to attempt a multi-dynastic history of the Great Wall was the 17th - century scholar Gu Yanwu . More recently, in the 1930s and 1940s, Wang Guoliang (王國良) and Shou Pengfei (壽 鵬 飛) produced exhaustive studies that culled extant literary records to date and mapped the courses of early border walls . However, these efforts were based solely on written records that contain obscure place names and elusive literary references . </P> <P> The rise of modern archeology has contributed much to the study of the Great Wall, either in corroborating existing research or in refuting it . However these efforts do not yet give a full picture of the Great Wall's history, as many wall sites dating to the Period of Disunity (220--589) had been overlaid by the extant Ming Great Wall . </P> <P> Western scholarship of the Great Wall was, until recently, affected by misconceptions derived from traditional accounts of the Wall . When the Jesuits brought back the first reports of the Wall to the West, European scholars were puzzled that Marco Polo had not mentioned the presumably perennial "Great Wall" in his Travels . Some 17th - century scholars reasoned that the Wall must have been built in the Ming dynasty, after Marco Polo's departure . This view was soon replaced by another that argued, against Polo's own account, that the Venetian merchant had come to China from the south and so did not come into contact with the Wall . Thus, Father Martino Martini's mistaken claim that the Wall had "lasted right up to the present time without injury or destruction" since the time of Qin was accepted as fact by the 18th - century philosophes . </P>

When did the chinese build the great wall