Today, we go underground and find a massive clue to where the previous civilization may have gone. We find that there are thousands of miles of catacombs present, all over the world. All because the cemeteries were over crowded? Or...is there a much darker secret to these tunnel systems that hold bones of the past, that are placed into geometric patterns. Are you ready to take this research to another level? Are you ready to go into the Catacombs?