In fact, tourists sometimes refer to "the blue line," "the red line," and "the green line," for example, when getting around, rather than trying to memorize the various numbers and letters that make up the NYC transit system.
You may have also noticed colored tiles in the various subway stations, and they may not line up with the color of the line that passes through that particular station.
So what exactly is the reasoning behind the colored tiles?
The answer dates back to a time when there were actually three separate subway systems, which eventually joined together to become the current system.
One of these systems, called the Independent Subway, operated the A, B, C, D, E, F, G and Q lines in the city, and architect Squire J. Vickers used a system of color-coded tiles to help riders remember which zones they were passing through.
Local stations between express stops would all contain the same color of tile on their walls, with the color changing each time a new express station was reached.
Unfortanately, many of the original tiles were removed during various renovations, but here is a comprehensive list of what shades were used, and where you can still find some of the originals tiles.
So, next time you're in the city, visit the New York Transit Museum to see the history of the subway system. Or better yet, go on an adventure to find these historic tiles yourself. Happy hunting.