A) The Great Barrier Reef The world’s largest living structure, according to the Guinness World Records, is the Great Barrier Reef.The Great Barrier Reef is located off the northeastern coast of Australia and stretches over 2,300 kilometers. It is made up of over 2,900 individual reefs and 900 islands, and can even be seen from outer space.It is considered a living structure because it is formed by billions of tiny organisms called coral polyps, which build up coral reefs over thousands of years. The reef provides habitat to thousands of marine species including turtles, fish, sea snakes, and even sharks.This natural wonder is not only the largest of its kind but also one of the most biodiverse ecosystems in the world. However, it is also under threat due to climate change, coral bleaching, and pollution. Protecting it is crucial for both environmental and scientific reasons.