Reefs have existed since at least the Cambrian, although the familiar coral-dominated, reefs of today are a much later arrival. A coral reef is much more than old rock lying on the sea bed. An intricate structure, complex set of relationships and distinct zones (reef top, reef sides, debris piles around the base) offer myriad places for animals to live and hide, which leads to incredible diversity.

Did you know?
Australia's Great Barrier Reef is larger than the Great Wall of China and is visible from space.


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