The world's largest reef system is the Great Barrier Reef, located off the northeastern coast of Australia. Stretching over 2,300 kilometers (approximately 1,400 miles), it comprises over 2,900 individual reefs and 900 islands. The Great Barrier Reef is renowned for its biodiversity, hosting thousands of marine species, including fish, corals, mollusks, and sea turtles. It plays a crucial role in marine ecology and is a UNESCO World Heritage Site, attracting millions of tourists each year for snorkeling, diving, and eco-tourism. However, it faces significant threats from climate change, pollution, and coral bleaching.