 Welcome to Spotlight. I'm Joshua Leo. And I'm Liz Wade. Spotlight uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live. On two days every year, most places on Earth experience 12 hours of light and 12 hours of darkness. These two days are the spring equinox and the fall equinox. On these two days, something special happens in the ancient city of Chichen Itza. The sun shines on one of the large and ancient stone structures built here. On this particular structure, it appears as if a snake made of light is moving slowly down the wall. This special effect depends on exact measuring of the sun's position. Experts think that ancient people called the Maya built this structure and the city many years ago. Experts say that the Maya's knowledge of the sun's position is unusual. Today's spotlight is on the ancient city of Chichen Itza. This city is in southern Mexico. Thousands of years ago, Chichen Itza was full of people. It was one of the most powerful cities of one of the most powerful ancient cultures, the Maya. But today, no one lives there. It is only a group of old buildings. However, people from around the world still come to see it. People come to learn about its ancient culture, the culture of the Maya people. The Mayan culture began almost 3,000 years ago. It grew in parts of Central America. Today, we know this area as the countries of Honduras, Mexico, Guatemala, and Belize. The Maya were skilled in many areas. Experts believe the Maya were excellent farmers. They also believe that the Maya created a complex written language. This may have been the first written language to come from the Americas. The Maya were also very good at mathematics. Their number system included the number zero. Mathematics experts say that using the number zero was an amazing thing. Other ancient cultures of the time did not use this number. However, people may know the Maya best for their calendar. A calendar separates time into different lengths, like months, days, and minutes. Making a very exact calendar is extremely difficult, but the Maya used their knowledge of mathematics and their interest in the stars to build a calendar. They carefully observed the movements of the sun, moon, and planets. This knowledge helped them to create their calendar. Other cultures also influenced and helped build parts of Chichen Itza. After a few hundred years, the Maya had left their city. They did return later. But then, about 1,000 years ago, a group called the Toltecs invaded the Maya. They did not conquer the Maya. Instead, the two cultures lived together. They even began to combine parts of their religious ceremonies. The Toltecs ruled the city for about 300 years. But they left the city. No one knows why. A little later, the Itza invaded the city. The Itza were invaders from a different area. The Itza built new parts of the city and they gave the city its name. The name Chichen Itza means mouth of the well of the Itza. However, the Itza did not rule the city very long. They left Chichen Itza after about 25 years. Again, no one knows why the Itza left. Experts know that the Toltecs and Itza built some of the buildings in the city of Chichen Itza. They used many images of their god in their building designs. The Toltecs and Itza worshipped the same god. Their god looked like a snake, but with feathers, like a bird. In the beginning of this program, we told you about a snake of light that climbs the wall of an ancient building. The snake of light is an image of this god. This interesting structure in Chichen Itza is the pyramid of Kukul Khan. A pyramid has four sides. These sides all come together at one point at the top. Each side on the pyramid of Kukul Khan has 91 steps. And there is one more step at the top of the pyramid. In all, there are 365 steps on the pyramid. This is the same as the number of days in a year. Some experts believe the Maya could have used this building to help them know when to plant crops. Each day the sun falls on a different step of the pyramid. This could be a way to follow the year. The people of Chichen Itza especially designed one building to observe and study the movement of the stars and planets. This building is the observatory. Experts say that the observatory is one of the most complex structures the Maya built. A set of steps went up and around and around the observatory tower. The steps made the observatory tower look like a large shell, like a snail's shell. The top of the observatory tower was a dome, that is, it was shaped like a half circle. And there were windows in the tower. Each window had a purpose. Experts believe that a person looking through one of these windows could see particular stars on particular dates. The Maya may have believed that studying the stars could tell them the future. But Chichen Itza was not only ancient buildings and studying stars. The citizens of Chichen Itza also had their own very popular ball games. Chichen Itza had the largest game area or court in Central America. The Maya probably played a game that was a little like football. Pictures of past games cover the walls of the ball court. But these pictures also show some violent events in these games. One picture even shows an official cutting off a man's head in the center of the game court. Around the year 1300, the Itza people left the city. Some Maya people still lived there. In 1517 Spanish invaders tried to invade the area around Chichen Itza. The Maya resisted for a time, but they could not resist the Spanish for long. The Spanish finally defeated the Maya. Sadly, Spanish invaders later destroyed many historical documents. So we may never know the full history of Chichen Itza. Today, people from all over the world visit the ancient ruins of Chichen Itza. The Secretary of Tourism in Mexico says that over a million tourists visit Chichen Itza every year. Large crowds gather at the Pyramid of Cuculcán to watch the snake of light climb. They see the carefully designed buildings. But today, the ruins will not be destroyed. Chichen Itza is a UNESCO World Heritage Site, an important part of the world's history. The writer and producer of this program was Liz Wade. The voices you heard were from the United States. You can listen to this program again and read it on the internet at www.radioenglish.net. This program is called The Ancient City of Chichen Itza. You can also leave your comments on our website and find us on Facebook. Search for Spotlight Radio. We hope you can join us again for the next Spotlight Program. Goodbye.