Great Wall of China Longer Than Previously Reported Ed Jones/AFP/GettyImages The Great Wall of China is already the longest man-made structure in the world but we may have to start calling it the Greater Wall of China. A five-year archaeological survey done by the State Administration of Cultural Heritage (SACH) found that the total length of the Great Wall was 13,170 miles long and reached across 15 provinces. This is more than twice the length previously thought. In 2009, SACH reported that the wall was 5,500 miles and stretched across 10 provinces. "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, the office director of the China Great Wall Society, told the China Daily. Archaeologists and mapping experts conducted field surveys in 15 provinces and found 43,721 sites related to the Great Wall, according to the report. 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 coal mining or building new roads, they destroy the remaining parts under the ground," Jianmin told the China Daily. The survey, which began in 2007, is part of the Great Wall protection project, which aims to preserve and protect the wall. "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," Jianmin told the China Daily. Construction of the Great Wall began more than 2,000 years ago to ward off invasions, but only 8 percent of the wall is still standing today. The Great Wall is one of the Seven Wonders of the World and was declared a UNESCO World heritage site in 1987.