All Saints Day is a Christian holy day honoring all saints who have attained heaven, both those officially recognized by name and the countless ordinary faithful who are not individually canonized. It's observed as a solemn feast in the Catholic Church and is also recognized by many other Christian communities, though customs vary by region and denomination. In many countries, including parts of Latin America, the Philippines, and Europe, it's marked by attending mass, visiting family graves, and cleaning or decorating them with flowers and candles, often blending with local cultural traditions of honoring ancestors.