Early in the 19th century, an invention arrived that would change the form and function of cities for generations.
Like all new technologies, it started out rudimentary, expensive, and nearly ineffectual. But it caught many imaginations and developed dramatically, eventually reaching the point of mass accessibility. Soon enough, it took aim at the public realm, with consequences that were indirect and unintended yet profound.
It reconfigured streets. It influenced the height of buildings. It altered foot traffic. It recast the relationship between buildings and streets. It changed how people felt about their cities and changed their points of reference. It turned cities into abstractions and, in some ways, turned city-dwellers against each other. Its influence nearly complete by the close of World War I, the invention has remained fundamentally unchanged, and is still universally celebrated, to this day.