“Children’s playground on roof of large New York [City] store while mothers are shopping,” ca. 1919, by Bain News Service, via Library of Congress Prints and Photographs Division (both photos).
There’s a good article on early 20th century New York City roof gardens here.
enclos*ure 
These just remind me that there is nothing new under the sun and all the folks who came before us were just as creative and sophisticated as we think we are. Both this one and the private rooftop garden are wonderful.