Folklore tells us fairy rings appear in the path made by tiny fairy feet as they dance in a ring. These rings are thought to be magical places.
The music and laughter of fairies is well known to draw people passing by the ring to stop a while. But be careful! Stepping into the ring can lead you to the fairy realm, sometimes forever, never to be seen again!
Trying to rescue someone from a ring is a hard thing to do. By reaching into the ring, with one foot firmly planted outside, grab hold of your captive friend and pull real hard. If you're both lucky your friend will come tumbling out of the ring to safety. But if your safely planted foot slips? You can both be lost. Probably better to watch, at a distance. Safely hidden.
For you unbelievers - the science.
A naturally occurring ring of mushrooms may grow overnight from a fungus underground. The rings appear during spring/summer months when the temperatures are hot and humidity is high. Some of these rings last a day or two others years. Some of these rings keep growing, adding to their size a little more each year. This happens when the fungus survives. They can keep growing, only stopping when they run into something to stop the spreading fungus - ie. trees, rocks, buildings or even another ring! They can be small, only 8" across to many miles. There is one, I believe in Scotland,that is several miles across and thought to be 700 years old!
All this scientific evidence is well and good. As for me? I look for the fairy lights, tinkling laughter, and small creatures happily dancing in a ring. After all we do have a Fairy Door set in the wall right next to the front door of our house.