Reefs are underwater structures made up of coral and other marine organisms. They provide essential habitats for a diverse range of marine life, including fish, invertebrates, and plants. Coral reefs, in particular, are known for their vibrant colors and complex ecosystems, supporting about 25% of all ocean species. Reefs can be found in tropical and subtropical waters around the world, often near coastlines. They play a crucial role in protecting shorelines from erosion and serve as important resources for fishing and tourism. However, reefs are threatened by climate change, pollution, and overfishing, making their conservation vital for marine biodiversity.