The Great Wall of China was once a very great wall indeed. A new survey shows that all the bits joined together would have stretched halfway round the equator.
State archaeologists have declared the Great Wall to be 21,196.18km (13,137 miles) long — more than double the previous estimate. The figure includes immense stretches that have vanished or are visible only to the trained eye.
The new length represents several times the width of China and it could still be selling the world’s biggest man-made structure short, possibly to the tune of 30,000km.
The latest survey confirmed longstanding fears that China’s most famous structure remains at constant risk from man and the elements. Huge portions of the wall, said the report, have collapsed. “The saving and preserving of the Great Wall’s relics should not be delayed,” it concluded.
The discovery of the full length of the Great Wall — last officially measured in 2009 at 8,851.1km — follows a five-year reassessment by the State Administration of Cultural Heritage and State Bureau of Surveying and Mapping. State-of-the-art surveying technology was employed, new regions were investigated and more institutions took part. To enhance accuracy, local governments in the 15 provinces, municipalities and autonomous regions through which the fortifications pass, helped with the measuring.
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Previous estimates had drawn heavily on historical records, but the most recent survey appeared to place a greater emphasis on physical evidence. Nevertheless, the surprise “discovery” of a missing 12,345km of Great Wall was more a feat of spin than archaeological prowess.
The global renown of the Great Wall of China has long depended on the misconception that there was only one. In reality, local warlords and more than a dozen dynasties built different walls across the country’s northern borders from well before China was unified under the Qin dynasty in 221 BC.
Some were made of mud or sticks and were washed away, and others were vandalised or stolen and are visible only as heaps of stones. Others involved building techniques so advanced that they have survived repeated earthquakes.
The Great Wall of worldwide popular imagination — turreted stonework snaking over mountain ridges — is the one reconstructed by the Ming emperors of the 14th century. It was primarily the Ming wall, with a length given as 8,851.1km. Only 8 per cent of it is classified as well preserved, while at least 31 per cent has disappeared.
“This new official length gives more in the way of quantity than quality to wall assessments but it is a very significant development in the way these structures should be understood,” said William Lindesay, a British researcher on Great Wall history. “Even now, though, there is still a very big gap in the survey and a lot of wall has gone missing. If you add together the most comprehensive maps of past walls, you get a total closer to 50,000 kilometres.”