The Earth is just one of the planets orbiting the Sun, but the only one where conditions are just right to support life. Explore the remarkable variety of life on Earth. How long has the Earth existed and what are the conditions that make it suitable for sustaining life? Why do penguins live in Antarctica and lions in Africa? Why do cedars grow in the tundra and vines in the jungle. This trip around the blue planet will help to answer these, and many more questions, about our unique and wonderful home.