The spectacular Great barrier Reef is the largest coral reef in the world. It is the largest structure in the world to have been built by living organisms. Find out more about this wonder down under in Great Barrier Reef. This is an AV2 media enhanced book. A unique book code printed on page 2 unlocks multimedia content. This book comes alive with video, audio, weblinks, slide shows, activities, hands-on experiments, and much more. Book jacket.