The world's largest living structure is the "Great Barrier Reef." Located off the coast of Queensland, Australia, it is composed of over 2,900 individual reefs and 900 islands, stretching over 2,300 kilometers. The Great Barrier Reef is a UNESCO World Heritage Site and is known for its stunning biodiversity, housing thousands of marine species, including fish, corals, mollusks, and sea turtles. Its vast ecosystem is vital for marine life and serves as a significant attraction for tourism. The reef faces threats from climate change, pollution, and other human activities, leading to ongoing conservation efforts.