As part of the Beijing-Kunming highway, a 240 km-long expressway links Ya'an City with Xichang City in southwest China's Sichuan Province.

Winding between the mountains, the Ya'an-Xichang Expressway runs across multiple rivers and 12 earthquake fault zones.

Most of the ladderlike expressway is made up of viaducts and tunnels.

It is acclaimed as an "expressway in the clouds" as it ascends by 7.5 meters for every kilometer.

With an investment of 20.6 billion yuan (about 3 billion U.S. dollars), its construction started in 2007 and took about 5 years.

The project has overcome harsh environment, geological challenges and engineering difficulties.

Produced by Xinhua Global Service.

Original title: GLOBALink|"Expressway in the clouds" in China's Sichuan