Christmas lights, also known as fairy or twinkle lights, are a popular holiday decorating tradition and widely used both inside and outdoors. From residential homes to commercial window displays, these sparkling ornaments add a magical feel to the holiday season. The popularization of Christmas lights dates back to the beginning of the 20th century. However, they werent widely used until the mid-century when advent of electricity made it easy to string them up and turn them on and off with the flip of a switch. During the 1950s and 1960s, as peoples interest in the tradition grew, so did the level of creativity. Christmas lights began to come in a wide variety of colors and sizes and today you can find them in nearly any hue imaginable. Not only do Christmas lights brighten up the holidays, they have health benefits, too. Studies show that when people observe Christmas lights, either in real-life or through computer simulation, their stress levels go down as serotonin levels rise. This is particularly beneficial for those who may be dealing with a difficult time around the holidays. Christmas lights are not only a holiday staple, theyre also a great way to spread festive cheer. Whether its a single string of white lights around your window, a bulb-covered arch or an entire yard or building wrapped in shinny strands of lights, the end result is the same: pure holiday joy.