This 1994 documentary by the History Channel details how the history and creation of the NYC subway system. The system started out with a single elevated line only in Manhattan. It quickly morphed into a 245-mile long underground rapid transit systems that spread to all ends of the city. Millions of people ride the system each year, making it one of the busiest rapid transit systems in the world today. Watch the documentary below to learn more about the history of rapid transit in NYC.