One of the most famous ancient structures in the world, El Castillo (The Castle) is located in Chichen Itza, on the Yucatan peninsula. What you see was built about 1100AD over the top of a much older pyramid. El Castillo exhibits many elements of the elaborate Mayan calendar system. The solar calendar is represented by the stairs, which total 365. There are 9 tiers, which when split by the staircases yields 18, the number of months in a year. There are 52 decorative panels on each side, equalling the number of years in the calendar cycle. In addition, on the solstices and equinoxes, unique shadows were cast by the pyramid edges on the stairs, marking both these significant religious events and as an indicator it was time to plant.
The Maya lived in what we now call Mesoamerica. Their civilization covered southern Mexico and the Yucatan, Guatemala, Honduras, and Belize.
Their history is divided into three periods: the Pre-Classic, Classic, and Post-Classic, lasting in total from about 400 BCE to the arrival of the Spanish in 1520 CE. Most of their great achievements in architecture, astronomy, and mathematics, occured during the Classic period, from about 200-900 CE. Even though the Maya were excellent record keepers and wrote their history and knowledge on hundreds of figbark paper books called codices, we will never know the full extent of their learning. Eventually, a Spanish priest ordered all the codices he could find burned. Only four books escaped the flames.