To see the feathered serpent descend the Mayan pyramid requires exquisite timing. You must visit El Castillo -- in Mexico 's Yucatán Peninsula -- near an equinox . Then, during the late afternoon if the sky is clear, the pyramid 's own shadows create triangles that merge into the famous illusion of a slithering viper . Also known as the Temple of Kukulkan , the impressive step-pyramid stands 30 meters tall and 55 meters wide at the base. Built up as a series of square terraces by the pre-Columbian civilization between the 9th and 12th century, the structure can be used as a calendar and is noted for astronomical alignments . The featured composite image was captured in 2019 with Jupiter and Saturn straddling the diagonal central band of our Milky Way galaxy . In a few days another equinox will occur -- not only at Temple of Kukulcán, but all over planet Earth . from NASA https://ift.tt/E2wnAdr