Great Pyramid of Cheops at Giza as astronomical observatory, showing how the passage to the subterranean chamber (not shown) acted as an observing tube, and how the passage on upper left could be used to observe time of solstice and equinox. Illustration of Piazzi Smyth's theory. Wood engraving 1891

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Great Pyramid of Cheops at Giza as astronomical observatory, showing how the passage to the subterranean chamber (not shown) acted as an observing tube, and how the passage on upper left could be used to observe time of solstice and equinox. Illustration of Piazzi Smyth's theory. Wood engraving 1891

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Photo credit: © World History Archive / Alamy / Afripics
License: Licensed
Model Released: No

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