The largest reef in the world located off the coast of Australia is the Great Barrier Reef. Stretching over 2,300 kilometers, it is the world's biggest coral reef system and comprises approximately 2,900 individual reefs and 900 islands. The Great Barrier Reef is renowned for its biodiversity, supporting a vast array of marine life, including thousands of species of fish, corals, and other organisms. It is a UNESCO World Heritage Site and serves as a major attraction for tourism, snorkeling, and diving. The reef is crucial for ecological balance and is also facing threats due to climate change and pollution.