Ancient Aliens is counting down the world’s top ten mysterious islands, including sites said to be home to giants, remote landmasses that are home to massive megalithic structures, and even islands that disappear into thin air. Could these incredible sites provide evidence of extraterrestrial visitation?

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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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