The 6-kilometer-long Aizhai mountain road has 13 hairpin turns stacked one upon the other as it climbs 440 meters in Xiangxi Tujia and Miao autonomous prefecture in Hunan province.

The road opened to traffic in September 1936. The construction was extremely difficult and dangerous, resulting in more than 200 deaths. Those who died rest in a cemetery with their fellow workers. The widest part of the road is no more than 7 meters; the narrowest is less than 4 meters — not enough to allow two cars to pass.

The Aizhai mountain road is part of highway G319, also known as the Hunan-Sichuan expressway, which connects Chongqing and the provinces of Guizhou, Yunnan and Sichuan. It is acclaimed as one of the most beautiful roads in Xiangxi and attracts many visitors.

A 1-kilometer suspension bridge over the Dehang Valley started construction in 2004 to alleviate the traffic on Aizhai mountain road. The bridge, which opened to traffic in 2012, is currently the longest suspension bridge in the world.

Tang Ziye contributed to this story.