The Great Wall is being destroyed from within by farmers Nearly two-thirds of the wall has now been damaged or ruined It is now being destroyed by farmers turning it into pathways, shelters and even fertilisers for crops The Great Wall of China is famous for being the largest man-made structure in the world stretching thousands of miles. Despite surviving more than 2,000 years, it is now in danger of being destroyed by farmers. Nearly two-thirds of the wall has now been damaged or ruined, according to Li Lin of the China Great Wall Society. Wonder of the world: The Great Wall of China is in danger of being destroyed by farming activity It was built by the Qin Dynasty about 2,200 years ago and was rebuilt by the Ming Dynasty 700 years later. Despite surviving for more than 2,000 years, it is now being destroyed by farmers living around the structure who has been turning it into pathways, shelters and even fertilisers for crops. In 2006, the government published the Great Wall Protection Regulations and a 10-year protection project. But the regulations have not been properly enforced in rural areas. It is also being threatened by the construction of roads. The Great Wall was built by a number of imperial dynasties as a defence barrier. During the Ming dynasty the Great Wall is believed to have stretched about 4,000 miles. Chen Jun, of Longxi County Museum, told CCTV.com: 'We tried to stop villagers from destroying the Great Wall. But the relics here are not included in the protection zone. Our hands are tied. Sections of the Wall north of Beijing and near tourist centres have been preserved and even extensively renovated Over the years the wall has been constantly rebuilt and repaired. It is made of stone, brick, tamped earth, wood, and other materials. The was built along an east-to-west line across the historical northern borders of China in part to protect the Chinese Empire against attack by various nomadic groups or military incursions by various warlike peoples or forces. Sections of the Wall north of Beijing and near tourist centres have been preserved and even extensively renovated. In poorer parts of the country the Wall is sometimes used as a village playground or is used as a source of stones for rebuilding houses and roads. Sections have also been affected by graffiti and vandalism. More than 37 miles in the Gansu province may disappear in the next two decades. In parts, the height of the wall has been reduced from more than 16ft to less than six feet. In addition to acting as a shield against border enemies the Great Wall was also used to enforce duties on goods transported along the Silk Road, to regulate or encourage trade and control immigration and emigration. Troop barracks, garrison stations, signaling capabilities through smoke or fire also helped to enhance the walls defensive characteristics. The wall goes from Shanhaiguan in the east, to Lop Lake in the west, an area that loosely represents the southern edge of Inner Mongolia. The entire length includes trenches and natural barriers such as hills and rivers. In an archaeological survey that took five years to complete, China's State Administration of Cultural Heritage announced yesterday that the wall measures 21,196.18 km (13,170.69 miles). That's considerably longer than the previous mark of 8,850 km (5,500 miles), which was based largely on historical records. The Great Wall was started in 500 BC and first linked up under leader Qin Shi Huang in about 220 BC to protect China's northern border and fend off foreign invaders. It grew to link up 15 provinces and was reinforced and extended many times during later dynasties. The previous estimate in 2008 only included structures built during the Ming Dynasty, which lasted from 1368 to 1644, and didn't count some of the ruins. Only 8.2 per cent of the wall built during the Ming Dynasty remains intact, 74.1 per cent is in poor condition, and in some sections, only its foundation remains, according to the report. A large amount of the wall has collapsed. The wall was put on the United Nations Educational, Scientific and Cultural Organisation's list of World Heritage sites in 1987.