New York City’s public transport branding story is a little bit complex, to be polite. Around the turn of the century, the NYC subway was not a system but a patchwork of private lines, each with its own look and feel. When they were joined into one institution in 1940, the MTA undertook an effort to make the loose mix of styles consistent, something it’s been trying to do—in fits and starts and with varying degrees of success—ever since. But you still know you’re in the NYC subway. Why is that? It's the mosaics.