Myths and legends - The Fairy Mythology - The Young Man in the Shian
Type of Spiritual Experience
The Fairies are again the old mystic people – the Picts who had not converted to Christianity - and it is likely the fairy turret was a broch
A description of the experience
The Fairy Mythology - Illustrative of the Romance and Superstition of Various Countries. by Thomas Keightley 
THE YOUNG MAN IN THE SHIAN
A FARMER named Macgillivray, one time removed from the neighbourhood of Cairngorm in Strathspey to the forest of Glenavon, in which the fairies are said to reside. Late one night, as two of his sons, Donald and Rory, were in search of some of his sheep that had strayed, they saw lights streaming from the crevices of a fairy turret which in the day time had only the appearance of a rock. They drew nigh to it, and there they heard jigs and reels played inside in the most exquisite manner. Rory was so fascinated that he proposed that they should enter and take part in the dance.
Donald did all he could to dissuade him, but in vain. He jumped into the Shian, and plunged at once into the whirling movements of its inhabitants. Donald was in great perplexity, for he feared to enter the Shian. All he could do therefore was to put his mouth to one of the crevices, and calling, as the custom was, three times on his brother, entreating him in the most moving terms, to come away and return home. But his entreaties were unheeded and he was obliged to return alone.
Every means now was resorted to for the recovery of Rory, but to no purpose. His family gave him up for lost, when a Duin Glichd or Wise man, told Donald to go to the place where he had lost his brother, a year and a day from the time, and placing in his garments a rowan-cross, to enter the Shian boldly, and claim him in the divine name, and if he would not come voluntarily, to seize him and drag him out; for the fairies would have no power to prevent him.
After some hesitation Donald assented. At the appointed time he approached the Shian at midnight. It was full of revelry, and the merry dance was going on as before. Donald had his terrors no doubt, but they gave way to his fraternal affection. He entered and found Rory in the midst of a Highland Fling, and running up, to him, seized him by the collar, repeating the words dictated by the Wise man. Rory agreed to go provided he would let him finish his dance; for he had not been, he assured him, more than half an hour in the place, but Donald was inexorable, and took him home to his parents.
Rory would never have believed that his half-hour had been a twelvemonth, "did not the calves grown now into stots, and the new-born babes now toddling about the house, at length convince him that in his single reel he had danced for a twelvemonth and a day."