Humans are just scratching the surface when it comes to what we know about our ancestors from the distant past. Lost cities, ancient texts, mysterious carvings, and unexplained structures provide clues to a long-forgotten time that goes further back in history than we could have ever imagined. From Egypt to China and even Antarctica, Ancient Astronaut theorists propose that the deeper we dig, the closer we will come to proving an extraterrestrial influence on Earth's ancient inhabitants.