![Ancient Aliens: Secrets of the Pyramid (S5, E1) | Full Episode Ancient Aliens: Secrets of the Pyramid (S5, E1) | Full Episode](https://i.ytimg.com/vi/4022OjgUkYs/maxresdefault.jpg)
For thousands of years, pyramids were the largest structures on Earth. See more in Season 5, Episode 1, "Secrets of the Pyramids." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens Subscribe for more from Ancient ...
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