On the wet Thursday evening of the 21st August, 1879, at about the hour of 8 o'clock, Our Lady, St. Joseph, and St. John the Evangelist appeared in a blaze of Heavenly light at the south gable of the Church of St. John the Baptist. Behind them and a little to the left of St. John was a plain altar. On the altar was a cross and a lamb with adoring angels. The Apparition was seen by fifteen people whose ages ranged from six years to seventy-five and included men, women, teenagers and children.

The poor humble witnessed distinctly beheld the Blessed Virgin Mary clothed in white robes with a brilliant crown on her head. Over the forehead where the crown fitted the brow, she wore a beautiful full-bloom golden rose. She was in an attitude of prayer with her eyes and hands raised towards Heaven. St. Joseph stood on Our Lady's right. He was turned towards her in an attitude of respect. His robes were also white. St. John was on Our Lady's left. He was dressed in white vestments and resembled a bishop, with a small mitre. He appeared to be preaching and he held an open book in his left hand.

The witnesses watched the Apparition in pouring rain for two hours, reciting the Rosary. Although the witnesses standing before the gable were drenched, no rain fell in the direction of the gable. They felt the ground carefully with their hands and it was perfectly dry as was the gable itself.

This area has become a large tourist attraction and hosts pilgrims daily not only from within Ireland, but from all around the world. A large cathedral was constructed on the site where mass is held on a regular basis from the last Sunday in April until the first Sunday in October for pilgrims visiting the shrine.

 The personal pilgrimage of Pope John Paul II in 1979, commemorating the centenary of the apparition, inspired an even greater devotion to the Shrine and endorsed the indelible seal of Vatican approval. Mother Teresa of Calcutta visited the Shrine in June of 1993. One and a half million pilgrims visit the Shrine annually.