China Saturday revealed the findings of a two-year investigation of the length of the Great Wall in the Ming Dynasty era, which estimate it to be more than 2,551.8 kilometers longer than earlier thought.

The Ming Dynasty (1368-1644) Great Wall is 8851.8 kilometers long, said the State Administration of Cultural Heritage (SACH) and State Bureau of Surveying and Mapping (SBSM).

Their joint investigation has increased the length of the Ming Dynasty Great Wall by 2551.8 km.

The Ming portion of the Great Wall is the most visually striking and well-preserved portion of the world famous monument.

The Great Wall was originally built by China's first emperor Qin Shi Huang (259-210 BC) in the Warring States Period (475-221 BC). It was listed as a United Nations World Heritage Site in 1987.

The newest survey result shows that the Ming Dynasty Great Wall starts from the Hushan section of the Great Wall in northeastern Liaoning Province, and ends at Jiayu Pass in northwestern Gansu Province.

It passes through 10 provinces, cities and autonomous regions in north China, including Liaoning, Hebei, Tianjin, Beijing, Shanxi, Inner Mongolia, Shaanxi, Ningxia, Gansu and Qinghai.

It has an artificial wall of 6259.6 kilometers, 359.7 kilometers of trench cutting part, and 2232.5 kilometers of natural defensive barriers such as hills and rivers.

GPS positioning system, infrared range finder and other mapping technologies have been used during the survey. The survey will now go on to research the Qin and Han Dynasty Great Wall and other portions of the Great Wall, lasting until late 2010.

(Xinhua News Agency April 19, 2009)