4. The cities of the Maya exhibit a unique style. The names of these cities have been forgotten. The ones we use today were made up by explorers and archeologists.

9. Ancient Maya discovered two fundamental ideas in math: Positional value and the concept of zero The goal of the game was to pass the ball around, without having it touch your hands, and then get the ball to pass through one of the rings. Since the rings were so high and players were not allowed to use their hands, it was extremely difficult to get the ball through a ring. In fact, when a player did manage to get a ball through a ring, that usually ended the game. The game ended otherwise when the ball touched the ground.

10. The Aztec civilization developed in the Valley of Mexico, wedged between high mountains, and surrounded by lakes that provided fish, waterfowl, potable water, and reeds for thatching and weaving. The climate was mild. The Aztecs extended for roughly 800 miles along a northwest-southeast axis.

11. Carved and painted serpent head at the base of the Templo Mayor. Tzompantli (skull rack) Templo Mayor. Painted reclining sacrificial Chacmool figure found inside the Templo Mayor.

13. The solar year was the basis for the civil calendar by which the Mexicas (Aztecs) determined the myriad ceremonies and rituals linked to agricultural cycles. The calendar was made up of 18 months, each lasting 20 days. The months were divided into four five-day weeks. The year was rounded out to 365 days by the addition of the five-day nemontemi (empty days), an omnious period marked by the cessation of normal activities and general abstinence.

14. The Aztecs were excellent engineers, creating causeways that linked the island city of Tenochtitlan with the mainland, aqueducts to carry fresh water, sewers to carry away waste, as well as dams and irrigation systems. They expanded the amount of arable land by building chinampas. Education was an important part of Aztec society. It was free and provided the opportunity for Aztecs to advance socially. There were special schools for advanced students. The Aztecs were polytheistic, held daily religious ceremonies, and held special reverence for the sun. The government was headed by an absolute ruler but most were elected to the position.