Coral reefs are vibrant underwater ecosystems made up of colonies of tiny animals called coral polyps. These polyps secrete calcium carbonate, which forms the hard structure of the reef. Coral reefs provide habitat and shelter for a diverse range of marine life, including fish, invertebrates, and other organisms. They are often referred to as the "rainforests of the sea" due to their rich biodiversity. Coral reefs are found in warm, shallow waters, primarily in tropical and subtropical regions. They play a crucial role in protecting coastlines from erosion and supporting local economies through tourism and fishing. However, coral reefs are threatened by climate change, pollution, and overfishing, making their conservation essential for marine health.