The pools sit in Glen Brittle, on the Allt Coir' a' Mhadaidh - the burn of the corrie of the wolf or dog - draining from the northern flank of the Cuillin into the River Brittle. The corrie itself, Coire na Creiche, takes its name from the old Gaelic for spoils, recalling the cattle raiders who used the enclosed amphitheatre as a refuge for stolen herds. The 1601 Battle of Coire na Creiche - the last clan battle ever fought on Skye - was decided here, at the same flat green ground where tourists now wade and bathe. The Cuillin gabbro above is some of the roughest mountain rock in Britain, frictioned in dry weather, treacherous in wet. The pools below are the run-off, gathered into small basins ringed with stone.

The blue is real, but it is geological rather than magical. The Allt Coir' a' Mhadaidh runs clear off the mountain - filtered through scree and minimal soil - and the basins are floored with pale gabbro and quartz, which reflect light upward and lend the water its luminous cast. When the sun catches the surface, the colour edges into a green-cyan that does not look like Scottish water. In flat overcast it dims to a steadier blue. Photographs taken from low angles on bright days are responsible for most of the publicity; in person, particularly in driving rain, the effect can be subtler than expected. The first known reference to 'the Fairy Pools' is in a 1931 guide book. There are no known associations with actual fairy folklore, despite the name.

The water is mountain-temperature year-round - somewhere between 4 and 10 degrees Celsius depending on the season, occasionally lower. Wild swimmers come anyway, and have for decades. The Open Cold Water swimming community treats the pools as a pilgrimage. A successful immersion involves stepping into a pool that feels not so much cold as electrically painful; the gasp reflex is involuntary. Most people last under a minute. Some plunge from the rock lip at the upper pool, swim a width, and clamber out shaking. There is no lifeguard, no railing, no cell signal beyond the path. The rocks are slick. The current can pull at the legs. In winter the path freezes; in summer the midge can be unbearable.

From the Glen Brittle car park the walk takes around twenty minutes - a stony path, sometimes muddy, with the Cuillin lifting north as you climb. The full sequence of pools extends about a kilometre up the burn. Lower pools are the busiest; higher pools, requiring small scrambles, are quieter. The view back down the glen, especially as the light goes, can be spectacular - the corrie opening to the sea at Loch Brittle, the Cuillin gathering darkness above. Rangers patrol now. There are signs about Leave No Trace, about the fragility of the path edges, about the volume of toilet paper that has had to be removed from behind boulders. The Fairy Pools have become a cautionary tale, but they remain very beautiful.