Fairy ring

A fairy ring, also known as fairy circle, elf circle or pixie ring, is a naturally occurring ring or arc of mushrooms. The rings may grow over ten meters in diameter and become stable over time as the fungus grows and seeks food underground. They are found mainly in forested areas, but also appear in grasslands or rangelands…

Fairy rings also occupy a prominent place in European folklore as the location of gateways into elfin kingdoms, or places where elves gather and dance…

Their names in European languages often allude to supernatural origins; they are known as ronds de sorciers ("sorcerers' rings") in France, and hexenringe ("witches' rings") in German. In German tradition, fairy rings were thought to mark the site of witches' dancing on Walpurgis Night, and Dutch superstition claimed that the circles show where the Devil set his milk churn. In Tyrol, folklore attributed fairy rings to the fiery tales of flying dragons; once a dragon had created such a circle, nothing but toadstools could grow there for seven years…

Scandinavian and Celtic traditions claimed that fairy rings are the result of elves or fairies dancing. Such ideas dated to at least the mediæval period; The Middle English term elferingewort ("elf-ring"), meaning "a ring of daisies caused by elves' dancing" dates to the 12th century. In his History of the Goths (1628), Olaus Magnus makes this connection, saying that fairy rings are burned into the ground by the dancing of elves…

Most often, someone who violates a fairy perimeter becomes invisible to mortals outside and may find it impossible to leave the circle. Often, the fairies force the mortal to dance to the point of exhaustion, death, or madness…

Text from Wikipedia. Photo via the excellent moqo-moqo.