All Saints' Day is a solemn holy day of the Catholic Church celebrated annually on November 1st. The day is dedicated to the saints of the Church, that is, all those who have attained heaven. It should not be confused with All Souls' Day, which is observed on November 2nd, and is dedicated to those who have died and not yet reached heaven. It is an opportunity for believers to remember all saints and martyrs, known and unknown, throughout Christian history. 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 canonised — those who are in Heaven, but whose sainthood is known only to God — have no particular feast day. All Saints Day is uniquely their feast.