At the turn of the 20th century, French imperialists in Indochina took advantage of the weakness of China's Qing government and built a 855-km narrow gauge railroad from Haiphong to Kunming. Thus, the remote southwestern province of Yunnan was linked to the outside world before it was linked to the rest of China. That railroad, a feat of engineering that took five years (and thousands of Chinese laborers' lives), lives on today as the only narrow gauge line left in China.
The 468-km Chinese section no longer carries passenger trains, but freight trains still use the line daily. All along the line, French colonial style station architecture, tunnels, and bridges remain for tourists and train buffs to explore.
One of the most beautiful bridges is the Renzi Bridge (人字桥), whose name in Chinese means "the bridge shaped like the character for person". The bridge is framed on both sides by tunnels, resulting in a dramatic sight from the valley below.
The village at the base of the mountain is hard to get to, with no public transportation or accommodations. We arrived by bicycle and were prepared to camp, but were offered beds by a family in the village. It's possible to climb up the adjacent hill to the railroad and walk along it as far as the tunnel entrance, but railroad police generally don't allow tourists inside. We managed to talk our way in, however. If you are so lucky, don't forget to bring your flashlight.