El Castillo has a staircase on each side featuring 91 steps. On top is the 365th step, representing the days of the year. The Mayan’s mastery of astrology also influenced the pyramid’s design. During the spring and winter equinox, a 37 yard long shadow of a snake travels along the stairs as the sun moves throughout the day. At the base of the Northern Staircase are two carvings of a feathered serpent. They represent Kukulkan, the serpent god and the most important Mayan deity.
