NEW LAYERS OF THE GREAT WALL OF CHINA -- ALTHOUGH IN SOME DISPUTE

HAIZIGOU, China — Zhang Lingmian was collecting walnuts in the countryside north of Beijing last autumn when a friend from a nearby village mentioned a mysterious structure in the mountains that had stumped locals. The retired cultural heritage official and his friend scampered uphill for two hours, whacking their way through the brambles after the path ran out. At the top of a 2,700-foot-high ridge, they reached a long trail of haphazardly placed rocks. Zhang says he immediately recognized what villagers called "the strange stones." "I knew right away it had to be part of the Great Wall of China," Zhang recalled on a recent hike to show off his discovery, about 50 miles from central Beijing.

Although most of the rocks had tumbled down, a few piles reached up to Zhang's chest. "The walls just had to be high enough to keep the barbarians from crossing with their horses," explained Zhang, who says he has been studying the wall for 33 years.

The Great Wall of China may be one of the most recognizable structures on Earth, but it is still in the process of revealing new layers of itself — to cries of disbelief and fury in some quarters. At a time when Beijing is asserting its territorial borders in the South China Sea, the discoveries are not universally applauded.

In early June, the State Administration of Cultural Heritage announced that it now believes the Great Wall is a stunning 13,171 miles long, if you put all of the discovered portions end to end. That's more than half the circumference of the globe, four times the span of the United States coast to coast and nearly 2 1/2 times the estimated length in a preliminary report released in 2009, two years into a project that saw the Chinese measure it for the first time.

"I'm very suspicious. China wants to rewrite history to make sure history conforms with the borders of today's China," said Stephane Mot, a former French diplomat and a blogger based in Seoul, who has accused the Chinese archaeologists of obliterating Korean culture.

Traditionally, the Great Wall was thought to extend from Jiayuguan, a desert oasis 1,000 miles west of Beijing, to Shanhaiguan, 190 miles east of the capital, on the Bohai Sea. In 2001, Chinese archaeologists announced that the wall extended deep into Xinjiang, the northwestern region claimed by the minority Uighurs as their homeland. Last month's announcement brought the eastern bounds of the wall to the North Korean border. That has outraged Koreans, who say the relics were built by ancient Koreans of the Koguryo kingdom, which occupied much of modern-day Manchuria from 37 BC to AD 688.

"I would say that these are not necessarily 'new discoveries.' Rather, we are looking more carefully at what is on the ground and trying to clarify whether it is the Great Wall or not," Yan Jianmin, office director of the China Great Wall Society, a nongovernmental organization of scholars and wall enthusiasts.

The survey of the Great Wall's length involved thousands of people, with 15 provinces and regions submitting the results of their research to Beijing. In all, the State Administration certified 43,721 known sites of Great Wall remains, up from 18,344 before the survey. (Portions of the list were published on the agency's website, although it did not include the locations in Heilongjiang and Jilin provinces that are contested by the Koreans. Maps will not be released because they are considered a state secret.)

What most people recognize as the Great Wall is the crenelated brick wall with watch towers and archer slits, the symbol of China from countless postcards and guide books. But there are many older walls dating from the 7th century that served the common purpose of defending China from invasion from the north.

The late Luo Zhewen, who was considered the top Chinese authority on the subject, once wrote that nothing should be considered the Great Wall unless it was at least 30 miles long, clearly defensive in nature and not circular, as opposed to a wall to keep your sheep from wandering