Excerpt:
By the mid-1800s New York City was one of the most crowded places on earth. Each year tens of thousands of new immigrants were arriving, spilling out into the streets and competing with established city dwellers for space. The congested streets and pokey transportation system were a source of constant complaint: "Modern martyrdom may be succintly defined as riding in a New York omnibus," groused one passenger. Another noted, "It would not be decent to carry live hogs thus--and hardly dead ones."
Then, in March 1888, a ferocious blizzard ground the city to a halt. Mountains of snow twenty feet high filled the streets, horse-drawn streetcars and omnibuses lay abandoned, the entire city was paralyzed. The snow left no doubt that New York needed an underground rail system and in 1894, after years of political obstacles, a plan was approved. Construction began in 1900.