The first-ever formal measurement of China’s Great Wall has determined that the structure is 21,196 kilometers (13,173 miles) long, the Xinhua News Agency reported today, citing the State Administration of Cultural Heritage.
An archaeological survey jointly conducted by the agency and the State Bureau of Surveying and Mapping since 2007 found that the pieces making up the Great Wall span 15 provinces, autonomous regions and municipalities in China, the report said.
The wall was first built more than 2,200 years ago to fend off foreign invaders, and was reinforced and extended many times during later dynasties, according to the Xinhua report.
A previous measurement of the Great Wall’s length was based on a 2008 preliminary survey that only included structures built during the Ming Dynasty, which lasted from 1368 to 1644. The measurement then was 8,850 kilometers (5,500 miles), the report said.