MASSES: MONDAY NOV 31 - 7.30PM; TUESDAY NOVEMBER 1: 7.30, 9, 12.10 and 7.30pm. All Saints Day is a special feast day on which Catholics celebrate all the saints, known and unknown. While most saints have a particular feast day on the Catholic calendar (usually, though not always, the date of their death), not all of those feast days are observed. And saints who have not been canonized—those who are in Heaven, but whose sainthood is known only to God—have no particular feast day. In a special way, All Saints Day is their feast.