Which is the largest reef system in the world?

The Great Barrier Reef is the world’s largest coral reef system, stretching about 2,300 kilometers along the coast of Queensland, Australia. It is composed of around 2,900 individual reefs and hundreds of islands, depending on classification. The reef supports a huge range of biodiversity, including more than 1,500 species of fish and many kinds of corals. It is one of the best-known marine ecosystems on Earth. The reef is under severe pressure from climate change, particularly coral bleaching caused by warmer ocean temperatures.