Zhangjiajie park:Great Walls of Nature

You may not know if you haven't been to Zhangjiajie in Hunan province, but local officials there are eager to spread the word about Yangjiajie and its stunning peak walls carved from mountains by nature over the millennia.

Part of the UNESCO World Heritage Site Wulingyuan Scenic and Historic Interest Area, Yangjiajie boasts about a dozen of the immense parallel walls of varying heights. Ongoing travel development projects will be completed in March, local travel officials said at a recent press conference at Diaoyutai State Guesthouse in Beijing.

"The peak walls are an integral part of the Zhangjiajie's landscape. A single stone wall is not uncommon in sandstone areas, but it's very rare that a group of such pretty and lofty stone walls maintain intact after all these years," says Chen Anze, a researcher from Chinese Academy of Geological Sciences, who visited Yangjiajie in December to investigate the landscape of the peak walls.

Zhangjiajie gained international fame when the Hollywood blockbuster Avatar in 2009 drew inspiration from its splendid mountains and pillar-like formations.

The descendants of generals of the Yang Family, who sacrificed themselves to defend their country from foreign invasion in the early Song Dynasty (960-1279), moved and settled in Yangjiajie many years ago. That's why the place got its name, and many scenic spots also have names related to the family to memorialize their ancestors.

Besides peak walls, Yangjiajie also has stone pillars, waterfalls and a special flower that changes color from white, red, purple, yellow to black from daybreak to sunset. But compared with other scenic spots in Zhangjiajie, the 34-square-kilometer Yangjiajie is like a virgin land and attracts less attention due to its steep mountains and inconvenient transportation. Many visitors to Yangjiajie have been self-guided wilderness enthusiasts.

To better promote its picturesque scenery, the local government invested 170 million yuan ($28.1 million) in a Yangjiajie cableway, and construction began in December 2012. Soon guests will be able to enjoy the peak walls from this mechanized perch, without exhausting themselves by climbing all the way.

The new cableway, the third in Wulingyuan, will make it easier to get to Yangjiajie from other scenic spots, and ease waiting lines in peak seasons by spreading tourists over more attraction sites.

In November 2010, geology and geomorphy experts from China and abroad - including Chen and Michael Crozie, who was then president of International Association of Geomorphologists - joined the Zhangjiajie Landscape International Symposium.

The experts agreed that Zhangjiajie's spectacular sandstone pillars, peaks, cliffs, valleys and caves are the result of quartz sandstone's weathering, erosion of rainwater and rock collapses due to gravity. They named this kind of landscape as Zhangjiajie Landscape, a unique type of sandstone landform.

"Yangjiajie's peak walls help us see Zhangjiajie Landscape's formation process. It's the masterpiece of nature, with great scientific and aesthetic values," Chen says. "Yangjiajie is a high-quality travel resource. The promotion of its peak walls to the market will upgrade Zhangjiajie's travel value as a whole," says Hu Zhiwen, vice-mayor of Zhangjiajie.

What's huge and solid stone and about 380 million years old?