Have we been visited by extraterrestrial being? Did these " Ancient Aliens" contribute to the birth of human civilization? Do our ancient monuments contain evidence of their presence? Join Philip Coppens, star of the History Channel's "Ancient Aliens" series as he reveals an array of astonishing truths about our history, including a radically different understanding of the pyramids and how they are constructed. Explore the origins of crystal skulls and how they were found. Learn the extraordinary stories behind monuments such as the Nazca Lines and Puma Punku, and who built them, and more.