These solar powered Christmas lights are the perfect way to add a festive touch to your holiday decor. They are powered by the sun, so you don't have to worry about plugging them in or changing batteries. They are easy to install and come in a variety of colors and styles to fit
From Wikipedia
Christmas lights are lights often used for decoration in celebration of Christmas, often on display throughout the Christmas season including Advent and Christmastide. The custom goes back to when Christmas trees were decorated with candles, which symbolized Christ being the light of the world. The Christmas trees were brought by Christians into their homes in early modern Germany.