This is an image of the Great Barrier Reef on the east coast of Australia - 2000 kilometers long. This is the largest reef on Earth today. (Courtesy LPI/NASA)

This is an image of the Great Barrier Reef on the east coast of Australia - 2000 kilometers long. This is the largest reef on Earth today. (Courtesy LPI/NASA)

This is an image of the Great Barrier Reef on the east coast of Australia - 2000 kilometers long. This is the largest reef on Earth today. (Courtesy LPI/NASA)

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