Poster. Swedish Flag Day in 1916. By Gustaf Ankarcrona [Public domain]. Nordic Museum's photographic studio, Nordic Museum. Available from Nordiska Museet and Wikimedia Commons.
June 6 is the National Day of Sweden. It was first celebrated in 1916, and was formerly known as Swedish Flag Day. The above poster is from 1916. The translation of the poster's text is "On June 6, the Swedish Flag Day, Stadium Skansen, Hasselbacken."