Stories of civilizations large and small disappearing without a trace can be found throughout history and across the globe. From a previously unknown civilization in China, a vanished race of giants, to the unexplained disappearances of the Classic Maya and the Anasazi--elements of these disappearances cannot be completely explained by conventional scholars. Although these cultures have vanished from the face of the Earth, they have left behind intriguing clues--clues, some say point to an otherworldly explanation. And if entire groups have been taken off planet, might there be a connection with sites connected to mysterious vanishings of people, planes, and boats in various locations throughout the world? Could examining these disappearances lead us to not only uncover evidence of extraterrestrial intervention in our remote past, but also reveal the consequences for the future of the human race?

Series host and Ancient Astronaut theorist, Giorgio Tsoukalos, explores the mystery of the Nazca Lines found in the desert region of Southern Peru. Hundreds of gigantic lines, some in the shape of animals, geometric patterns and even an alien-like being, extend for miles over a vast section of the arid plain. Scholars are divided as to who built them, and why. Some Ancient Astronaut theorists believe that the massive markings have an extraterrestrial connection, and perhaps the ancient people of the region created these gigantic figures in tribute to the gods who visited them. While the area was abandoned nearly 2000 years ago, remains of ancient Nazca people have been found with strange, elongated skulls. Could this be evidence that there really was contact with "sky people" as ancient legends describe?