The deepest sinkhole in the world. Located in Fengjie, China. 30° 45′ 1.8″ N, 109° 28′ 12.36″ E. It’s 1.3 mile down and up on stairs. It is not a long walk but very tiring. To me, it is much harder than 10 miles hike in high mountains. If you go visit Three Gorges Dam, make sure […]