The Great Barrier Reef is the world's largest coral reef system, composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometres. It is located in the Coral Sea, off the coast of Queensland, Australia. The reef supports a wide diversity of life and was selected as a World Heritage Site in 1981.

The Great Barrier Reef is under threat from climate change, pollution, and other human activities. Rising ocean temperatures cause coral bleaching, a process where corals lose their vibrant colours and may die if the temperature remains high for too long. In recent years, there have been several major bleaching events affecting large portions of the reef.

Conservation efforts are underway to protect this natural wonder. These include reducing pollution, controlling outbreaks of crown-of-thorns starfish (which eat coral), and implementing sustainable tourism practices. Scientists are also researching ways to help corals adapt to warming waters.