Atoll

An atoll is a ring-shaped coral reef, island, or series of islets that encircle a lagoon, usually formed around the rim of a submerged volcano. Over time, coral growth builds up around the volcanic island, which erodes and sinks, leaving a lagoon in the center. Atolls are common in warm ocean waters and provide unique habitats for marine life. They are important for biodiversity, local communities, and sometimes tourism, offering a delicate balance between natural beauty and ecological significance.