I see these in the forests around where I live quite often in the autumn. In Norwegian they're called "heksering", translates to witch ring, and have historically been thought of as a bad omen. Specifically a remnant of gathering places for witches, hence the name.

The species in this case is Leucopaxillus giganteus, which is edible, and due to the unique fairy rings, unusually easy to identify. Though I still don't dare try them because only young specimens are edible and mature ones are known to contain KCN...