A fairy ring is a naturally occurring ring of mushrooms. They are also known as pixie’s rings, faerie circles, or elf circles. The English believed that fairy rings were where fairies came to dance and celebrate, the mushrooms of the rings were used as stools for the fairies to recuperate during the evenings festivities.
It is also traditionally believed that to enter a fairy ring was to put yourself at risk of being “spirited away” by the fairies and to break the mushrooms creating the circle would incur their anger.
Huh, didn’t know this.