When investigating finds from the past, lost civilizations and excavations from antiquity, scientists always come across unknown treasures and peculiarities. It usually takes a few years before all the secrets of a find are unraveled, for others it takes decades or one only bases oneself on assumptions. But then there are always finds - especially of old technologies - that can not be explained to this day. The records of this are lost and the former knowledge of these civilizations has long since died out. Here are some examples of technologies from the past that still puzzle many researchers today.