El Castillo, also known as the Temple of Kukulcan is a Mesoamerican step-pyramid that dominates the center of the Chichen Itza archaeological site in the Mexican state of Yucatán. The temple building is more formally designated by archaeologists as Chichen Itza Structure 5B18.

Mesoamerican pyramids form a prominent part of ancient Mesoamerican architecture. Although similar in some ways to Egyptian pyramids, these New World structures have flat tops and stairs ascending their faces, more similar to ancient Mesopotamian Ziggurats. The largest pyramid in the world by volume is the Great Pyramid of Cholula, in the east-central Mexican state of Puebla. The builders of certain classic Mesoamerican pyramids have decorated them copiously with stories about the Hero Twins, the feathered serpent Quetzalcoatl, Mesoamerican creation myths, ritualistic sacrifice, etc. written in the form of Maya script on the rises of the steps of the pyramids, on the walls, and on the sculptures contained within.