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:
Big Apple
Today the name enjoys exclusive ubiquity in literature and speech referring to New York City, and is used with regularity by journalists and news-headline writers across the English-speaking world.