Archaeologists, mapping experts find 43,721 sites related to the Greatwall structure crisscrossing the country making its overall length to be at 21,196.18 km, according to the latest survey published by China`s State Administration of Cultural Heritage.
"The previous estimation particularly refers to Great Walls built in the Ming Dynasty (1368-1644), but this new measure includes Great Walls built in all dynasties," Yan Jianmin, office director of the China Great Wall Society, an NGO founded by specialists and scholars to protect the Great Wall, told state-run China Daily.
Qin Shi Huang, the first emperor of the Qin Dynasty (221-206 BC), was famous for building the Great Wall, the world`s largest human-made structure. But construction of the wall had begun as early as 7th century BC, the new survey said.
The oldest section of the Great Walls that has been found is the Great Wall of Qi State in Shandong province, and the Great Wall of Chu State in Henan province. Both date back to the Spring and Autumn Period (770-476BC), according to Yan.
"As thousands years pass, some ground structures disappear, and we do not know where the walls used to be. When some local governments or companies develop the land, like coalmining or building new roads, they destroy the remaining parts under the ground," Yan said.
"Now we are clear about the location of the Great Wall, so the government can take steps to protect the walls, and local governments are clear about their responsibility to protect the walls," he said.
The survey was performed jointly by the State Administration of Cultural Heritage and the National Administration of Surveying, Mapping and Geo information. Eager to cash on the new findings, officials here planned to open more sections of the Great Wall to accommodate the mounting number of tourists.
Kong Fanzhi, chief of Beijing`s cultural relics bureau said last week the Great Wall sections are overloaded on weekends and holidays. The Great Wall in China was built over many dynasties starting 2,200 years ago.
Among all the sections, a 600-km section lies in Beijing, most of which has been preserved in good condition, said Wang Yuwei, an official on cultural relics protection with the bureau.
Wang said new sections were also found covered in bush or blocked behind higher walls during the survey.
Archaeologists and mapping experts conducted field surveys in 15 provinces, municipalities and autonomous regions including Heilongjiang, Hebei, Beijing, Shaanxi and Xinjiang, and found 43,721 sites related to the Great Wall.
"In Shaanxi province, we knew of only 20 per cent of the early walls (before the Ming Dynasty) before the survey," Li Gong, a researcher in charge of the Great Wall survey at the Shaanxi Provincial Institute of Archaeology said.
"Some of the early Great Wall has a tiled roof, so when the walls collapse there would be shattered tiles. Even with the clue, we still spent a whole month before we spotted the first defensive structure," Li said.
The Great Wall was a defensive structure built by ancient Chinese empires for protection from marauding tribes. Some walls are built on a ridge and others use steep mountain cliffs as a natural fence, and link the cliffs and walls with watchtowers.
"In the past we did not count the defence cliff into the whole length of the Great Wall, but they surely are part of the defensive structure. Now we count it, so this would make the total length longer too," Li said.
The survey is only the first step in a larger project to protect the Great Wall. The State Administration of Cultural Heritage launched a protection project in 2006, and planned on a long-term maintenance map to be completed before the end of the 12th Five-Year Plan (2011-15) period, the daily report said.