Niezalezna(.)pl: Catholic Church celebrates All Saints' Day on November 1. In Polish tradition, it is also a day of reflection and visiting the graves of loved ones (Halloween was not celebrated in Poland until lately but it's not popular).
All Saints' Day is one of the oldest Christian holidays. Its origins date back to the first centuries, when the Church honored martyrs and the faithful visited their graves on the day they were born into heaven, i.e., on the anniversary of their death.
According to tradition (at least in Poland), on All Saints' Day, the faithful visit cemeteries where their relatives and friends are buried. Candles placed on gravestones on this day symbolize hope and memory of people who have passed away, and flowers are a symbol of selfless love.
In Poland, All Saints' Day is a national holiday, but if you want to get anywhere, you need to account for traffic around cemeteries and to/from there, all day long.