Chichen Itza, located in the Yucatan of Mexico, is the apex of Maya archaeological sites. A UNESCO World Heritage Site since 1988, it is one of the New Seven Wonders of the World.
The Kukulkan Pyramid (also called "El Castillo") is the architectural highlight of the ruins. This structure is famous for having various Maya calendar cycles represented in the number of steps, platforms, sides, and levels, all of which are aligned with the equinox sun, such that on those days only, a serpent-shaped shadow descends the steps. The pyramid has four stairways, each with 91 steps and a platform at the top, making a total of 365, equivalent to the number of days in a calendar year.