Complex sentence: Most pilgrims arrive by Trinity Sunday, when the Blessed Sacrament is taken in procession through the sanctuary; the following day the Lord of Qoyllur Rit'i is taken in procession to the grotto of the Virgin and back.
Split into simpler sentences: Most pilgrims arrive by Trinity Sunday, when the Blessed Sacrament is taken in procession through the sanctuary. The following day, the Lord of Qoyllur Rit'i is taken in procession to the grotto of the Virgin and back.