All Saints' Day (in the Catholic Church officially the Solemnity of All Saints and also called All Hallows or Hallowmas), often shortened to All Saints, is a solemnity celebrated on 1 November in Western Christianity, and on the first Sunday after Pentecost in Eastern Christianity, in honour of all the saints, known and unknown.
Roman Catholic Obligation
In the Catholic Church All Saints Day is a Holy Day of Obligation, meaning going to Mass on the date is required (unless one is ill or elderly). However, in the United States, All Saints Day is not considered a Holy Day of Obligation when it falls on Monday or Saturday, as well as having no obligation at all in Hawaii.
In the Philippines, this day, called "Undas", "Todos los Santos" (literally "All Saints"), and sometimes "Araw ng mga Namayapa" (approximately "Day of the deceased") is observed as All Souls' Day. This day and the one before and one after it is spent visiting the graves of deceased relatives, where prayers and flowers are offered, candles are lit and the graves themselves are cleaned, repaired and repainted.