Big Apple
"The Big Apple" was popularized as a name for New York City by John J. Fitz Gerald in a number of horse-racing articles for the "New York Morning Telegraph" in the 1920s. The earliest of these was a casual reference on 3rd May, 1921:
New York Nights: Success in the City
For as long as you can remember, you have had only one desire: to leave the small town in Alabama where you grew up and take on one of the most glamorous and exciting places in the world: New York City! Guess what? Your dream has finally come true! You have enough cash to see you through forty days, so establish yourself in the Big Apple: make friends, find a job, and start yourself on the path to becoming rich and famous. Who knows, you might even find true love! Remember, time is always ticking away, so if you haven’t made a name for yourself in forty days, it’s right back to square one!