Beautiful scenery along the Yaxi highway, a "ladder-like sky road" in China. (Photo/newssc.org)

Yaxi highway, a 240-kilometer-long road connecting Ya'an and Xichang in southwest China's Sichuan province, is regarded as a "ladder-like sky road". The road is a combination of viaducts and tunnels. The total length of the 25 tunnels along the road is about 41 kilometers.