Baby cages were a 20th century invention that allowed city-dwelling parents without balconies, yards or other outdoor spaces to give their babies some fresh air; these cages were fitted into windows and allowed the child to be outside of an apartment or house while still being in a purportedly contained, safe space. While modern parents may balk at the concept, some early 1900s parents thought the baby cage was a fantastic idea because it would allow young children to get fresh air without requiring an adult to take the baby out of the home.
Patented in the 1920s by an American woman named Emma Read, baby cages were made of metal wire and were typically lined with blankets and other soft material to make babies comfortable. The original patent for the baby cage included a design for a small roof that could fit over the wire top in order to protect babies from the elements and, perhaps, from things that may be dropped from above and fall into the wire cage. Though the baby cage never really took off, enough people used it that there are some photographs of babies inside these contraptions, including toddlers who appear perhaps too big for the space.