El Castillo during Equinox week - Fotografia de stock

During the spring/autumn equinox, and 1 week before and after, a phenomenon will occur in the late afternoon when the setting sun casts its shadow on El Castillo pyramid. The Mayans built the pyramid with a head of a serpent at the bottom of its main stairway. The shadow cast onto this stairway will form an illusion of the Feathered Serpent (Kukulkan) slithering down the pyramid. On the actual day of the equinox, the crowds will be many times bigger.