Introduction to One Thread Sky: is the narrowest part of Bailong Gorge, where there are vague plank roads built by the ancients. The cliffs on both sides are lush with pines and cypresses. When walking on the plank road, you can only see a line, so it is called "One Thread Sky". Climbing up the ladder, you will see towering rocks and cliffs on both sides, and the roar of Bailong Waterfall at your feet is like thunder.