Exploring the complex structure of the coral reef itself and the wildlife that lives on it. So vast it is visible from space, the reef is actually built by tiny animals in partnership with microscopic plants. It is a place full of surprises that is always changing, responding to the rhythms of weather, tide, sun and moon. Within this magical and intensely crowded world, this episode reveals how the amazing reef creatures compete and cooperate - from deadly fish-hunting snails to sharks that can walk on land, fighting corals and parrot fish that spin sleeping bags every night. Remote cameras, cutting-edge underwater macro and digital time-lapse photography have captured many sequences which have never been filmed before, providing completely fresh perspectives on this extraordinary natural wonder.

Originally released by BBC Worldwide Learning, 2012. Streaming video file encoded with permission for digital streaming by Infobase on November 21, 2019.