Despite all the things we’ve learned about ancient history, there’s still many unexplained archaeological discoveries. Most discoveries give us a window into the past. However, there are some discoveries that defy popular knowledge about ancient civilizations and their capabilities. Like, how was Stonehenge built? What are the Nazca lines for? What’s the deal with the devil’s bible? But, just because we don’t understand something, doesn’t mean we can’t try and learn from it. Eventually, we’ll figure it out. In the meantime, it’s fun to enjoy the mystery of the past. Check out these 25 mysterious archaeological discoveries no one can explain.