Which is the city that "never sleeps"?
The City That Never Sleeps is a well-known nickname for New York City that was popularized by Frank Sinatra, in the Theme from New York, New York's words:
I want to wake up in a city that never sleeps
And find I'm a number one, top of the list ...
Many answers, from restaurants that do not close, to lots of nightlife at all hours, and so forth.
But the biggest reason, perhaps -- New York City is the only city in the world with a subway system that does not close. So you can go out until 4am and still get home. Or you can do a job that starts at 5am and -- no problem.
Growing up, one great memory was ending a long night by taking a date on the Staten Island Ferry. It was cheap -- usually about 25 cents round trip. You get a boat ride through New York Harbor, past the Statue of Liberty and Ellis Island. And, if you go out at 3 or 4am, you will see workers coming in from Staten Island on their way into Manhattan at 4 or 5am.