Skyglow (or sky glow) is the illumination of the night sky or parts of it. The most common cause of skyglow is artificial light that emits light pollution, which accumulates into a vast glow that can be seen from miles away and from high in the sky. Skyglow from artificial lights is common throughout the world and can be observed over most cities and towns as a glowing dome of the populated area. Skyglow's light domes can be large, as in that over a city, or small, as in that over an over-illuminated shopping center or a stadium.