25. The Baigong Pipes
In a remote area of China that is inhospitable to human life, there three mysterious triangular openings at the top of a mountain that contains ancient iron pipes that date back to the ancient Chinese dynasties. The pipes run deep inside the mountain with some routing into a deep saltwater lake nearby. What’s strange about this discovery is that the pipes are clear of debris and they were obviously meant for some purpose, however, archaeologists can’t figure out what. Some theories involve it once being an ancient astronomy lab. Unfortunately, we may never know.