El Castillo, also known as the Temple of Kukulcán, is a step pyramid located in the ancient city of Chichen Itza in Mexico. Built by the Maya civilization around the 12th century, it stands approximately 24 meters tall and features four staircases, each with 91 steps, leading to a temple at the top. The pyramid is famous for its architectural precision, particularly during the spring and autumn equinoxes when the sun casts shadows that create the illusion of a serpent slithering down the stairs. El Castillo is a UNESCO World Heritage Site and a popular tourist destination, showcasing the ingenuity of Maya engineering and astronomy.