China has included the Shu Path on its list of places believed to be worthy of UNESCO World Natural and Cultural Heritage status.

A prospective list has been sent, and preparations for a formal application are expected to be finished in 2017, said Zhang Hu, chief of the Sichuan World Heritage Application Office of the provincial Department of Housing and Urban-Rural Development

Twenty-two counties and districts in Sichuan covering more than 3,700 square kilometers will be included in the application process.

"Neighboring Shaanxi and Gansu provinces may also join in the project," Zhang said.

In ancient times, all roads leading from the outside to Sichuan were referred to as the Shu Path, including those from Shaanxi and Gansu.

Surrounded by mountains, Sichuan, called Shu in ancient times, was known for its inaccessibility. That became widely known partly due to a line from Chinese poet Li Bai (AD 701-762). He lamented: "Traveling on the Shu Path is as difficult as ascending to heaven".

The most famous section of the Shu Path is about 600 kilometers long. It starts at Chengdu, then passes Deyang and Guangyuan in Sichuan before ending in Hanzhong in Shaanxi. Construction of the section started around 316 BC. It was built on mountains so precipitous that the awe-struck Li Bai was inspired to mention it.

When builders approached the Mingyue Gorge in Guangyuan, they found it impossible to continue because the cliffs were too steep. So they chiseled three levels of holes in the rock, and inserted wooden beams. The upper beams were covered by planks to form a road for pedestrians, while buttresses were anchored at the second and third levels.

During the Three Kingdoms period (AD 220-280), Zhuge Liang, prime minister of the Shu Kingdom, used the plank road to transport troops to fight rival forces in the Wei Kingdom in North China.

The plank road was burned and rebuilt many times during wars. Now part of it has been restored to allow visitors to admire the man-made wonder.

"When I walked on the plank road built on dangerous cliffs beside the gushing Jialing River, I had awesome respect for those who built it," said Wu Dan, a woman from Beijing.

The Sword Gate Pass, a towering V-shaped mountain pass-the one that gave rise to a household idiom, "One man at the pass keeps 10,000 men at bay" - witnessed countless battles during the Three Kingdoms and is in the Guangyuan section of the Shu Path.

huangzhiling@chinadaily.com.cn