The patron of Pompeii is Our Lady of the Rosary, and her two dates are 8 May and the first Sunday of October. On those days tens of thousands of the faithful come to town for the Supplication to Our Lady of Pompeii.
The prayer is known as the Hour of the World, because devotees of the Rosary recite it simultaneously wherever they happen to be. The sanctuary that hosts it, now a pontifical basilica, was willed by Saint Bartolo Longo, who drove the birth of the modern town beside the excavations.