Info from Wikpedia:
In Sweden, a folkpark is a public recreation space, usually featuring large grassed areas, trees, children\’s play facilities, etc. Most towns and cities have a folkpark.
These parks were originally created by the labour movement so that workers and their families could have a place to unwind. In larger folkparks, there is sometimes a bandstand or stage, and they are used for concerts and other entertainment. Summer folkpark tours are a traditional part of the touring circuit for bands, etc. (End wiki-info)
In 1891-1892 the first Folkpark was opened in Malmö after that the concept spread over the whole country.