Fairy rings
Fairy rings are naturally occurring circles of mushrooms. The mushrooms grow on the ground in a circular shape. Some are small and some are as big as 600 metres in diameter.
Cause
Fairy rings are formed by an individual fungus growing underground. The fungus gives many small threads, called mycelium, in a circular shape. After a year , the mushrooms grow out of the ground at the edge of the circle, forming the fairy ring. The circle will start as small in size, and get bigger as it grows older.
Favourable conditions.
Fairy rings are mostly found in woodland and grassy areas. The best time for their growth is late summer to early autumn, and they appear after wet weather.