Inventing the Public Park

[A] The nineteenth-century public park was not designed as a place to enjoy. It was designed as a medical instrument. Cities were understood to be unhealthy because their air was stagnant, and a large open space planted with trees was expected to move and cleanse that air across the district around it, in the way a window ventilates a room. [B]

[C] The theory was wrong in its details, since the diseases the parks were meant to prevent turned out to travel through water rather than air, but the institution outlived the reasoning that produced it. That is a common enough pattern and it is usually told as luck. [D] It is better understood as a case of a design being specified loosely enough to serve a purpose nobody had named: the parks were required to be large, open to everyone without charge, and defensible against later building, and those three requirements are exactly what a public space needs in order to become the thing a park is now valued for. The medical argument was mistaken, but the constraints it imposed were the right ones.