A blue plaque is a permanent sign installed in a public place in the United Kingdom and elsewhere to commemorate a link between that location and a famous person or event, serving as a historical marker.The world's first blue plaques were erected in London in the 19th century to mark the homes and workplaces of famous people. This scheme continues to the present day, having been administered successively by the Society of Arts (1867–1901), the London County Council (1901–1965), the Greater London Council (1965–1986), and English Heritage (1986 to date).Many other plaque schemes have since been initiated in the United Kingdom. Some are restricted to a specific geographical area, others to a particular theme of historical commemoration. They are administered by a range of bodies including local authorities, civic societies, residents' associations and other organisations such as the Transport Trust, the Royal Society of Chemistry and the British Comic Society. The plaques erected by these schemes are manufactured in a variety of designs, shapes, materials, and colours: some are blue, others are not. The term ""blue plaque"" may be used narrowly to refer to the official English Heritage scheme, but is also often used informally to encompass all similar schemes.There are also commemorative plaque schemes throughout the world such as those in Paris, Rome, Oslo, Dublin; and in other cities in Australia, Canada, Russia, and the United States. The forms these take vary, and they tend to be known as historical markers.