Delores Wells, Christa Speck / enjoying the sunroom at the Playboy Mansion in Chicago / photo for the pictorial “Playmate Holiday House Party" / Playboy, December 1961.
The first jungle gym was invented in 1920 and patented by lawyer Sebastian Hinton in Chicago. It was sold under the trademarked name Junglegym. The term "monkey bars", was first documented in 1955 [wikipedia]
