The Guoliang tunnel is one of those roads that is famous because of how it was made rather than how fast you can ride it. In the 1970s, with no road to the outside world and no help coming, villagers from Guoliang decided to cut one themselves, through the cliff face rather than around it. They sold animals to buy hammers, chisels and explosives and worked for about five years, mostly by hand, until a gallery roughly 1.2 kilometres long ran along the inside of the rock wall, wide enough for a small vehicle and lit by a row of rough openings that look straight out over the gorge.
Riding it today is slow and unforgettable. The tunnel is narrow, the roof is low and uneven, the surface can be damp and dusty in places, and the openings in the wall flash light and dark across your visor as you pass. Through each one the drop opens below, and from the outside those same openings are what make the famous photograph: a cliff with a line of irregular windows punched along its face. Approach with dipped headlight, low gear and a lot of patience, because buses, cars and walkers share the same space and passing places are few.
The rock itself is quartz sandstone, laid down in layers when this region lay under shallow seas and later lifted and cut by rivers into the walls of the Taihang. It is hard enough to hold a gallery like this and soft enough to carve, which is part of why the villagers succeeded. Below the tunnel the road continues in hairpins and ledges toward the valleys, with more viewpoints and short walks to waterfalls and pools in the gorges.
The best plan is to come early in the day, before the shuttle buses start running in strength, and to stop at the pull-outs at either end rather than in the tunnel itself. In wet weather water seeps through the rock and the floor becomes slick, so take it seriously. There is nothing in the way of services inside the scenic area apart from village kiosks and guesthouses, so fill up in Huixian before the climb, carry water, and expect an entrance ticket at the scenic-area gate. It is a short piece of road, but it is a story worth telling at dinner.