An adventure playground is a specific type of playground for children. Adventure playgrounds can take many forms, ranging from "natural playgrounds" to "junk playgrounds," and are typically defined by an ethos of unrestricted play, the presence of playworkers (or "wardens"), and the absence of adult-manufactured or rigid play-structures. Adventure playgrounds are frequently defined in contrast to playing fields, contemporary-design playgrounds made by adult architects, and traditional-equipment play areas containing adult-made rigid play-structures like swings, slides, seesaws, and climbing bars.
Harry Shier, in Adventure Playgrounds: an introduction (1984) defines an Adventure Playground this way:
The first planned playground of this type opened in Emdrupvej (or Emdrup), Denmark, in 1943. In 1948, an adventure playground opened in Camberwell, England. The term "junk playground" is a calque from the Danish term skrammellegeplads. Early examples of adventure playgrounds in the U.K. were known as "junk playgrounds," "waste material playgrounds," or "bomb-site adventure playgrounds." The term "adventure playground" was first adopted in the United Kingdom to describe waste material playgrounds "in an effort to make the ‘junk’ playground concept more palatable to local authorities."
The first junk playgrounds were based on the ideas of Carl Theodor Sørensen, a Danish landscape architect, who noticed that children preferred to play everywhere but in the playgrounds that he designed. In 1931, inspired by the sight of children playing in a construction site, he imagined "A junk playground in which children could create and shape, dream and imagine a reality." His aim was to provide children living in cities the same opportunities for play that were enjoyed by children living in rural areas. The first adventure playground was set up by a Workers Cooperative Housing Association in Emdrup, Denmark, during the German occupation of the 1940s. The playground at Emdrup grew out of the spirit of resistance to Nazi occupation and parents' fears that "their children's play might be mistaken for acts of sabotage by soldiers." Play advocates sometimes emphasize the importance of adventure playgrounds for children of color in the United States, where policing "can feel like a kind of occupation."