St. Nicholas Day (Dzien Świętego Mikołaja) is celebrated on the 6th December each year in Poland.
For many Poles, St. Nicholas Day marks the start of the Christmas season proper in Poland. Tradition says that St. Nickolas (Sw. Mikolaj) visits homes and leave small gifts under pillows, on windowsills and in shoes for the children who live there. These presents are generally sweets, chocolates, gingerbread (pierniczki) and other edible treats. In past times, some Polish families would leave hay, apples, or carrots out for the donkey on which St. Nicholas was believed to be riding.
Many families also choose to put up their Christmas decorations and decorate their tree on Mikołajki (the 6th December). And Xmas lights are switched on by shops, businesses, and local councils in many towns and cities throughout Poland.