Great Wall of China even longer than thought !

Photo. The Wall was listed as a Unesco world heritage site in 1987. The structure is a series of walls first linked up more than 2,000 years ago.

The wall, the world's largest man-made structure, was built to protect the northern border of the Chinese Empire, and it`s the only man-made building structure visible from the moon.

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.

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.

Another brick in the wall
China announced in October 2002 the discovery of a lost section of the Great Wall which was hidden for centuries beneath shifting sands.
 
The segment was found in the north-western region of Ningxia which was crucial to imperial China's border defences, the state news agency Xinhua reports.

In August 2002, Chinese experts announced the discovery of other important ruins in Gansu, which borders Ningxia.

Thirty unrecorded Great Wall beacon towers, two fortified castles and two auxiliary buildings were discovered during their expedition.

Experts said the newly-discovered sections of the wall were built during the Ming Dynasty (1368-1644), and stretch from Hu Mountain in northern Liaoning province to Jiayu Pass in western Gansu province.

The project will continue for another 18 months in order to map sections of the wall built during the Qin (221-206BC) and Han (206BC-9AD) Dynasties, the report said.

Archaeologists had lobbied for the survey to be done to provide scholars with an accurate understanding of the construction.

Known to the Chinese as the "long Wall of 10,000 Li", the Great Wall is in fact a series of walls and earthen works begun in the 5th Century BC and first linked up under Qin Shi Huang in about 220BC.
 
Stein Morten Lund, 23 April 2009

Additional information
The Great Wall of China was built from the 7th century BC onwards to defend the northern borders, updated length  8,850km, and, on average, 3.5m high and 4.5 m wide.