The Poster was made for the Greater Berlin's 100 year anniversary.  Berlin had been part of the Province of Brandenburg since 1815. On April 1st 1881, the city became an the urban district Berlin, a city district separate from Brandenburg. The Greater Berlin Act was passed by the Prussian Parliament on 27 April 1920 and came into effect on 1 October of the same year. The new Prussian province then termed Greater Berlin acquired territories from the Province of Brandenburg, which is how we know Berlin today. Context aside, this poster was exhibited at the Rotes Rathaus, home to the governing mayor and the Senate of Berlin as part of their celebration of these 100 years.