Christmas lights are lights used for decoration around Christmas. The use of decorative, festive lighting during the Christmas holiday season is a long standing tradition in many Christian cultures, and has been adopted as a secular practice in a number of other non-Christian, or predominantly non-Christian, cultures (notably in Japan).
The tradition of using small candles to light up the Christmas tree dates back to at least the middle of the 17th century. However, it took two centuries for the tradition to become widely established first in Germany and soon spreading to Eastern Europe.
Candles for the tree were glued with melted wax to a tree branch or attached by pins. Around 1890, candleholders were first used for Christmas candles. Between 1902 and 1914, small lanterns and glass balls to hold the candles started to be used.
The first known electrically illuminated Christmas tree was the creation of Edward H. Johnson, an associate of inventor Thomas Edison. While he was vice president of the Edison Electric Light Company, a predecessor of today's Con Edison electric utility, he had Christmas tree light bulbs especially made for him.
Over a period of time, strings of Christmas lights found their way into use in places other than Christmas trees. Soon, strings of lights adorned mantles and doorways inside homes, and ran along the rafters, roof lines, and porch railings of homes and businesses. In recent times, many city skyscrapers are decorated with long mostly-vertical strings of a common theme, and are activated simultaneously in Grand Illumination ceremonies.