Horca del Inca

This unusual monolithic construction cut out of natural rock ridges is found on a hilltop behind the village of Copacabana. The name, "The Inca's Gallows", is somewhat misleading as it predates the Incas by several centuries and was not used by a hangman. In fact it has been proved that it is an astronomical observatory. This image was taken on the spring equinox (21 September), when shadows from nearby rock fins project directly onto the monoliths (this also occurs on 21 March, the autumn equinox). Soon after sunrise on the winter solstice (21 June) the sun shines directly through a hole cut into a nearby rocky ridge and onto the lintel.
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Titicaca134934
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