TV Ancient Aliens - Season 2 Episode 4 : Underground Aliens Ancient Aliens - Season 2 Episode 4 : Underground Aliens 7/10 by 295 users If extraterrestrials influenced human history, can evidence of their existence be found in hidden tunnels and caverns around the world? Could a cave in Ecuador contain metallic books inscribed with secrets of alien technology? Was an ancient underground city in Turkey built with alien help... or as a refuge from an alien attack? Rumors of the U.S. military working alongside aliens in a secret base inside a mesa in New Mexico continue to swirl, Native American legends mention strange inner-Earth beings, and recent archaeological discoveries in the Yucatan may point to an extraterrestrial reality behind. Details Casts Posters Images Title Ancient Aliens - Season 2 Episode 4 : Underground Aliens Alternative Titles Nos ancêtres les extraterrestres, 远古外星人, Ancient Aliens - Neue Erkenntnisse, Alienígenas ancestrales, Generacion alien, Alien Theory, 古代の宇宙人, Goście z Przeszłości, Drevni vanzemaljci First Air Date 2010-04-20 Last Air Date 2026-03-05 Number of Episodes 285 Number of Seasons 22 Genres Documentary, Mystery, Sci-Fi & Fantasy, Networks History, Casts Robert Clotworthy, Giorgio A. Tsoukalos, Ariel Bar Tzadok, Jonathan Young, David Childress, Erich von Däniken, Linda Moulton Howe, David Wilcock, George Noory, Philip Coppens, Nick Pope Plot Keywords , Narrator (voice) Robert Clotworthy Self Giorgio A. Tsoukalos Self Ariel Bar Tzadok Self Jonathan Young Self David Childress Self Erich von Däniken Self Linda Moulton Howe Self David Wilcock Self George Noory Self Philip Coppens Self Nick Pope Self Mike Bara Self Bill Birnes Self Hugh Newman Self Robert M. Schoch Self Nick Redfern Episodes List Ancient Aliens Season 2 :Episode 1 Mysterious Places Mysterious Places 2010-10-28 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 2 Gods & Aliens Gods & Aliens 2010-11-04 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 3 Underwater Worlds Underwater Worlds 2010-11-11 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 4 Underground Aliens Underground Aliens 2010-11-18 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 5 Aliens and the Third Reich Aliens and the Third Reich 2010-11-25 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 6 Alien Tech Alien Tech 2010-12-02 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 7 Angels and Aliens Angels and Aliens 2010-12-09 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 8 Unexplained Structures Unexplained Structures 2010-12-16 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 9 Alien Devastations Alien Devastations 2010-12-23 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings... Ancient Aliens Season 2 :Episode 10 Alien Contacts Alien Contacts 2010-12-30 Did intelligent beings from outer space visit Earth thousands of years ago? From the age of the dinosaurs to ancient Egypt, from early cave drawings...