Under the rule of the Underground Group's publicity officer Frank Pick, appointed in 1908, many of the major and unsung minor artists from Britain, Europe and the USA produced their finest work as poster advertising from the London Underground. In its heyday of art patronage, the company was displaying as many as 40 new works a year. Artists were given the greatest possible scope for self-expression, and worked in every subject and style. The stations and platforms of the Underground became one huge modern art gallery - the biggest are gallery in the world - featuring over the years more than 3000 original posters.