is a tower, building, or other type of structure designed to emit light from a
system of lamps and lenses, and to serve as a navigational aid for maritime
pilots at sea or on inland waterways.
mark dangerous coastlines, hazardous shoals, reefs, and safe entries to
harbors, and can assist in aerial navigation. Once widely used, the number of
operational lighthouses has declined due to the expense of maintenance and use
of electronic navigational systems.