Fairy rings are circular patterns of mushrooms that appear in grassy areas. They form when a fungus, such as mycelium, spreads underground and depletes nutrients in a circular area, causing mushrooms to grow at the edges. These rings can vary in size and may be found in forests, fields, and lawns. The name "fairy ring" comes from folklore, where they were believed to be magical places where fairies danced. While they are often associated with myths, fairy rings are a natural phenomenon that can indicate the presence of certain types of fungi, contributing to the ecosystem's health.