The name of the world's largest reef system is the Great Barrier Reef. Located off the coast of Queensland, Australia, it is the largest coral reef system in the world, stretching over 2,300 kilometers (1,400 miles) and encompassing approximately 344,400 square kilometers (133,000 square miles). The Great Barrier Reef is composed of over 2,900 individual reefs and 900 islands. It is a UNESCO World Heritage Site and is renowned for its stunning biodiversity, housing thousands of marine species, including vibrant corals, fish, and sea turtles. The reef faces threats from climate change, pollution, and overfishing, leading to ongoing conservation efforts.