Some of the tunnels are as straight as a pencil and you can see the light at the end. Others however are curved such that you will be enveloped in pitch-black darkness for a short time unless you take alone a flashlght, which is advisable but not absolutely essential.

The trail was originally built by Taiwan Power Company during the early stages of their plans to develop hydroelectric power in the area, plans that included damming many parts of the gorge in ways that would have destroyed within years.