Chichen Itza in Yucatan, Mexico, was founded by the Mayan Itza tribe between 435-455 AD. This impressive three-mile area is one of the world's greatest archeological showplaces, from the Sacred Well, to the Great Ball Court and its temple groupings. The largest pyamid is El Castillo. Ninety-five exterior steps climb to the pyramid's top. Its construction was planned so that during Vernal Equinox the setting sun would cast a shadow of a serpent writhing down the steps. Over 40,000 people travel to watch this event yearly.