What is the relationship between the Mayan calendar and the Kukulkan pyramid?

The Kukulkan pyramid, also known as El Castillo, is aligned with specific astronomical events related to the Mayan calendar. During the spring and fall equinoxes, the sunlight creates a shadow that resembles a serpent descending the pyramid's staircase, symbolizing the feathered serpent god Kukulkan. This alignment highlights the Mayan's advanced understanding of astronomy and their intricate calendar system.