The popular celebratory customs associated in various countries with Christmas have a mix of pre-Christian, Christian and secular themes and origins. Popular modern customs of the holiday include gift giving, Christmas music and caroling, an exchange of Christmas cards, church celebrations, a special meal, and the display of various decorations, including Christmas trees, lights, nativity scenes, garlands, wreaths, mistletoe, and holly. In addition, several closely related and often interchangeable figures, known as Santa Claus, Father Christmas, Saint Nicholas and Kris Kringle among other names, are associated with bringing gifts to children during the Christmas season and have their own body of traditions and lore. Because gift-giving and many other aspects of the Christmas festival involve heightened economic activity among both Christians and non-Christians, the holiday has become a significant event and a key sales period for retailers and businesses. The economic impact of Christmas is a factor that has grown steadily over the past few centuries in many regions of the world.