Christmas lights are decorative lights used during the Christmas holiday season. In most residential areas, these are typically popular outdoor ornamental lighting set up during the festive season, often on public buildings for display. Christmas lights have been in use since the late 18th-century and have since become a tradition in many parts of the world. Christmas lights come in many shapes, sizes and colors and often feature distinctive designs such as snowflakes, stars or Santa. There is no standard size for Christmas lights and many vary in length and number of bulbs depending on individual taste. The bulbs are usually small and encased in clear plastic, and typically arranged in strings or strands of varying lengths. These strands are connected to a power source, and are usually hung on buildings or trees. Christmas lights come in both incandescent and LED varieties, as well as many colors. Incandescent lights produce a warm yellow-hued light which many people find inviting and festive. LED lights, on the other hand, are usually a bit brighter and require less care and upkeep. The lifespan of LED Christmas lights is substantially longer than that of incandescent lights. Regardless of the type and design of Christmas lights, they are a common feature of holiday season celebrations. Christmas lights create a festive atmosphere that cannot be replicated in any other way. They add warmth, personality and beauty to the holiday season for many people around the world.