Steve Backshall goes beneath the surface of Australia's Great Barrier Reef to discover the crucial conditions that allowed a tiny coral building block to create the largest living structure on the planet. He unravels the complex mosaic of reef environments to reveal the key to the micro-world's success, but discovers that life on this coast is not always easy. Nutrient-poor water, enormous storms and rising seas should make it impossible for such a vibrant ecosystem to exist here, so what allows the Great Barrier Reef to not only survive but flourish as the largest reef on Earth? A BBC Production.

Originally released by BBC Worldwide Learning, 2012. Streaming video file encoded with permission for digital streaming by Infobase on October 03, 2015.