In the late 19th century, doctors began recommending that parents in urban apartments regularly expose their children to fresh air. It was believed this would strengthen the child’s immune system and increase her general health and vigor.

While physicians such as Dr. Luther Emmett Holt advised simply placing an infant’s basket near an open window, some parents took it a step further.

Eleanor Roosevelt, who by her own admission “knew absolutely nothing about handling or feeding a baby,” bought a chicken-wire cage after the birth of her daughter Anna. She hung it out the window of her New York City apartment and placed Anna inside for her naps — until a concerned neighbor threatened to report her to the authorities.

The first commercial patent for a baby cage was filed in 1922 by Emma Read of Spokane, Washington. The cages became popular in London in the 1930s among apartment dwellers without access to backyards.

Ultimately, their popularity declined. It is possible that this was connected to safety concerns.