Much of the subway’s complexity stems from the fact that it originated as two competing companies. There was the Manhattan based IRT and the Brooklyn based BMT, who not only laid their tracks without heed to each other, but sometimes worked at cross purposes. The end result is that the NYC subway is one of the more convoluted underground transit systems in the world.

1924 IRT

The two companies produced separate maps that focused on their own lines, often providing sketchy detail for the competition. This IRT map from 1924 shows all the boroughs, but doesn’t include any BMT lines. Often the maps would portray the company’s lines as straight and the competition’s as crooked. “The idea was simple,” writes Andrew Dow in Telling the Passenger Where to Get Off. “The straighter the line, the faster the trip would look to a customer.”