The Center for the Study of Extra-Terrestrial Intelligence defines a “Close Encounter of The Fifth Kind” as direct human contact and communication with extraterrestrial life. But is this a classification that will only be useful in the distant future, or have such encounters already taken place… and within the highest levels of the U.S. government?

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Ancient Aliens is counting down the world’s top ten mysterious devices, from strange, grooved disks found in a cave in China to an ancient Greek computer to an incredible crystal skull unearthed in Mexico. Might these sensational artifacts provide evidence of extraterrestrial visitation?

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Meteor impacts have significantly altered our world, creating the perfect environment for the rise of humankind and delivering metals essential to the development of an advanced civilization. But could new evidence reveal that celestial objects have been directed to Earth by an alien intelligence?

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The Mutual UFO Network–better known as MUFON–is the world’s leading organization devoted to the scientific investigation of unidentified aerial phenomena and other unexplained encounters. With more than five decades of investigations, could MUFON’s extensive database contain definitive proof of extraterrestrial visitation?

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Ancient Aliens is counting down the world’s top ten pyramid sites, from a valley in Peru with over 250 hidden pyramids to an ancient Greek city with mysterious 4800-year-old ruins to Egypt’s famous Giza Plateau. Could the extraordinary structures that stand at these sites provide evidence of extraterrestrial visitation?

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The towering obelisks of ancient Egypt weigh hundreds of tons and each was perfectly carved from a single granite rock. While mainstream scholars identify them as monuments to the pharaohs, Ancient Astronaut Theorists suggest they may have served a technological purpose–they powered a technology that allowed for communication with the gods who came from the stars.

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The discovery of the ancient megalithic site of Karahan Tepe in southern Turkey turned the world of archaeology on its head, displaying engineering skills far beyond what the people of the time were thought to be capable of. But could new evidence reveal that this more than 11,000-year-old complex was built not by humans…but giants?

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Ancient Aliens has examined the oldest and most mysterious rock art on Earth–up close and in person. Now, Giorgio Tsoukalos takes a look back at the incredible hieroglyphs, petroglyphs, and geoglyphs that he believes tell a worldwide story–of alien visitation.

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