Adventure Playgrounds are also often called Natural Playgrounds or Junk Playgrounds. According to Wikipedia, Adventure Playgrounds are typically defined by an ethos of unrestricted play, the presence of playworkers, and the absence of adult-manufactured or rigid play-structures.
“It is the child in man that is the source of his uniqueness and creativeness, and the playground is the optimal milieu for the unfolding of his capacities and talents.” ~ Eric Hoffer
Here is a list of some of the top Adventure Playgrounds:
“Children seek out rough and tumble play, climbing to heights and moving their bodies at high speed — activities that are a critical way that children learn about risks and cope with fears”