Grand Central Station

Imagine you're at work, and it's a crazy day: the phone is ringing off the hook (a lot!), people are coming and going, and it's generally a hive of activity. You might be inclined to sit back and exclaim, "It's like Grand Central Station in here!".

Grand Central is one of the main railway stations in New York City, and I can tell you from experience, it's a very busy place, with a constant hustle and bustle.

The British equivalent would be "It's like Piccadilly Circus!"