There’s a strange set of pips that poke out of the top of a mountain in the Qinghai Province of China. These pipes, lead down into a series of caves in Mount Baigong, and run through it all. No one knows how they got there.

The pipes are made of a combination of iron and silica, and based on the surrounding rock, there’s evidence that these pipes were created and installed well before the iron age, before we could even make things out of iron, or drill such deep holes in the mountain. The pipes stretch for feet throughout solid rock, with no discernible way to figure out how they got there. As well, there’s no evidence that humans actually ever lived in the area, so either this is a freaky natural occurrence, or some mysterious force created a drainage system for reasons we can’t understand.