The basilica of Knock is a Roman Catholic Church of the Latin Rite located in the small town of Knock, in County Mayo in the West Region of Ireland. It was designed in modern architecture style with concrete materials by architect Daithi Hanly, and completed in 1976. The basilica, which can accommodate approximately 10,000 people, serves the Roman Catholic Archdiocese of Tuam, and it is part of the Knock Shrine grounds that incorporates four other churches, including the Apparition Church, the place where, on Thursday evening of 21 August 1879, the Blessed Virgin Mary, Saint Joseph, and Saint John the Evangelist appeared, the old Parish church, the Blessed Sacrament Chapel, and the Chapel of Reconciliation.