In Peru, this month celebrates the Roman Catholic dogma of the Immaculate Conception of the blessed Virgin Mary. Celebrated on the 8th December, exactly 9 months before the Nativity of Mary 8th September.
Mary herself is the Immaculate Conception. That is, the day does not refer to Mary's conceiving Jesus by the Holy Ghost, but to the conception of Mary in the womb of her mother, St. Anne, by Mary's father. What makes her conception immaculate is not that she was conceived by the Holy Ghost of a virgin, as was Christ Our Lord, but that from the very moment of her conception, she was filled with grace by God, Who knew, in His omniscience, that she would say "yes" to the Angel Gabriel and become the Mother of the Savior.