April 20, 2009

Great Wall longer than previously thought

China's historic Great Wall is about 1,550 miles longer than previously thought, a government survey reveals.

The wall had been thought to be around 3,975 miles long, but all its parts added together total 5,533 miles, the Mainichi Daily News reported Monday.

The surveyors followed the wall's remnants through 10 provinces, special autonomous regions and municipalities from the easternmost Ming section of the wall in Liaoning province to its westernmost extension in Gansu province, the newspaper said. The surveyors also counted 5,723 signal fire towers along the way.

The new total included previously uncounted ditches, depressions and natural obstacles such as cliffs to the 3,813 miles of man-made defensive wall.

Major construction of the Great Wall dates to the first emperor of the Qin dynasty (221-206 B.C.), and was expanded centuries later. The well-preserved wall dating from the Ming dynasty (1368-1644) was mapped by the Chinese State Administration of Cultural Heritage and State Bureau of Surveying and Mapping from 2006 to 2008 using modern technology such as global positioning.