This Ghost Light put in nearly 100 years of service at The Capitol Theater in Madison, Wisconsin. The superstitious tradition behind the ghost light is ancient, dating back to at least the time of Shakespeare. According to legend, a candle would be left burning on the stage to dispel the ghosts of previous performances, especially if those performances had gone badly. The candle may also well have deterred people trying to break into the theater, of course, by suggesting that someone was present.
In time, theaters began to use a ghost light like this for liability reasons as well as the more mystical explanation for the light's presence. Some say that ghost lights are left on to allow the ghosts in the theater to perform at night, while others fall back on the tradition that the light is supposed to keep ghosts away.