A coral reef is a vibrant underwater ecosystem made up of tiny animals called coral polyps. These polyps live in colonies and build hard structures from calcium carbonate, creating the beautiful formations we see in oceans. Coral reefs provide a home for many marine species, including colorful fish, sea turtles, and various invertebrates, making them one of the most diverse habitats on Earth. Coral reefs are often referred to as the "rainforests of the sea" because of their rich biodiversity. They also play a crucial role in protecting coastlines from erosion and supporting local economies through tourism and fishing. However, they face threats from climate change, pollution, and overfishing, making their conservation essential for marine life and human communities alike.