Great Britain (Welsh: Prydain Fawr, Scottish Gaelic: Breatainn Mhòr, Cornish: Breten Veur, Scots: Great Breetain), also known as Britain, is an island to the north-west of Continental Europe. It is the ninth largest island in the world, the largest European island and the largest of the British Isles. With a population of about 60.0 million people in mid-2009, it is the third most populous island in the world, after Java and Honshū. It is surrounded by over 1,000 smaller islands and islets. The island of Ireland lies to its west. Politically, Great Britain also refers to the island itself together with a number of surrounding islands, which constitute the territory of England, Scotland and Wales.
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and used as an aid to navigation for maritime pilots at sea or on inland waterways.
Lighthouses mark dangerous coastlines, hazardous shoals, reefs, safe entries to harbors, and can also assist in aerial navigation. Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and replacement by modern electronic navigational systems.