The Great Wall of China is even greater than previously thought, according to the first detailed survey to establish the length of the ancient barricade.
A two-year government mapping study found that the wall spans 8,850km (5,500 miles) - until now, the length was commonly put at about 5,000km.
Previous estimates of its length were mainly based on historical records.
Infra-red and GPS technologies helped locate some areas concealed over time by sandstorms, state media said.
The project found that there were wall sections of 6,259km, 359km of trenches, and 2,232km of natural defensive barriers such as hills and rivers.
The study was carried out by the State Administration of Cultural Heritage and the State Bureau of Surveying and Mapping. - Read More