Guoliang Tunnel in the Taihang Mountains in Henan Province, China

Guoliang Tunnel in the Taihang Mountains in Henan Province, China

For years, the only way into and out of the remote village of Guoliang in the Taihang Mountains was a steep, pedestrians-only passage called the Sky Ladder. But in 1972, 13 villagers set to work with hand tools and by 1977, had carved this tunnel through the side of the mountain. Not a single power tool was used for the boring. Though it did finally provide automobile access to the village, the side effect was an increase in tourism, with visitors making the trek through the tunnel that offers stunning, death-defying views of the sheer mountain wall on the way up to Guoliang.