The Pyramid of El Castillo at Chichen Itza was constructed to correspond to the Mayan astrological year. Each side contains 91 stairs, with a final step at the summit, for a total of 365 steps. The Pyramid was built to commemorate the equinoxes, which are the two days of the year when there is an equal amount of day and darkness. By counting the steps, it is possible to tell the date exactly. The first eclipse of the sun on August 13, 582 A.D., prompted the builders to finish the structure immediately. It was probably used as a temple for religious ceremonies. The number 365 has many meanings for people around the world. For Christians, it represents the life of Jesus Christ. For Muslims, it refers to the complete cycle of the earth's daily rotation around its axis (day and night). For astronomers, it is the number of steps required to climb Mount Everest. No one knows why the builders of Chichen Itza chose to construct their great monument without any help from outside sources. Some historians believe they may have been trying to show off their own power, while others think they may have been trying to mark the beginning or end of some period in Maya history. Whatever their reasons, today we can still count every step up the pyramid. After the city had been abandoned, anyone who went up the pyramid would meet another person at the top. This is because everyone died climbing the steps - the only ones left alive were the very old or very young.