Welcome to THIS IS AMERICA in VOA Special English. I'm Bob Doughty along with Barbara Klein. This week on our program, we explore a UNESCO __________(1) Site in the American Southwest, near the city of Carlsbad, New Mexico. Carlsbad Caverns National Park contains more than __________(2) caves below the surface of the desert. Most are closed to the public. But anyone can visit the main __________(3), one of the largest caves in the world.Huge. Incredible. Inspiring. Words like these come to mind as visitors enter a world of __________(4) and cold, almost __________(5) meters under the ground.An elevator lowers you into the world of Carlsbad Cavern, the big cave at Carlsbad Caverns National Park.Silent, except for the voices of guides and visitors. And not completely dark. The __________(6) has enough lighting to see many of the beautiful formations all around. The temperature is about thirteen degrees Celsius.A cavern is a large cave. But Carlsbad Cavern is really a long series of chambers. One of these is called the __________(7). The Big Room is more than three hectares big. The ceiling is seventy-seven meters high. The Big Room is the single largest __________(8) chamber ever found in North America.