5. Pneumatic Tube Transport
In the late 1800s, cities such as New York and London dabbled with pneumatic tube transport for both people and mail. The Beach Pneumatic Transit even operated briefly beneath Manhattan, whisking passengers through tunnels using air pressure. However, expansion proved prohibitively expensive, and the concept faded. Though modern projects like the Hyperloop draw inspiration from these early ideas, large-scale pneumatic transit for people has yet to materialize. Discover more at Smithsonian Magazine.
