Streetlights, usually arranged in rows along roads as well as park alleys and squares, illuminate urban areas in the evening and at night. At the beginning of the 19th century kerosene and gas lamps appeared in the streets of London and Paris, however, after several decades they were replaced by electric streetlights. In order to obtain optimal beam range two (or more) lighting luminaries are installed on one lighting pole. Streetlight can be used as a decorative element of the city as they are often decorated with beautiful details made by carvers or blacksmiths.
