NYC Playground Movement
According to CUNY Professor Roger Hart, the playground movement in New York City (c. 1900) attempted to replace free play with formalized play - playgrounds - due to fears for the safety of children playing in the streets, but also fears of these mostly immigrant, low-income children as unassimiliated threats who needed to be occupied with more wholesome, structured activities.
Hart argues that children resisted - including by spreading broken glass on streets to slow traffic impeding play - because playgrounds failed to meet the complexity of their interests and developmental needs. He instead points to adventure playgrounds with loose parts, natural environments, and play facilitators, and community gardens with play spaces planned by children themselves as examples that support the development of a more democratic society in which children are able to "invent their own worlds" and participate in building society as opposed to simply being passive recipients of it.
On a related note, an article (registration required) published in the New York Times about a "new kind of playground" being built in Lower Manhattan is accompanied by an in-depth multimedia feature entitled "Playgrounds Grow Up" that is narrated by New York City Parks Commissioner Adrian Benepe and takes the viewer through the history of play provision in the city.