Examples of "quintessential restaurants" in various places

I am curious to hear about what people view as the essential restaurants in given destinations. I am referring to specific places that have been well trafficked for decades (if not more) without much change, and still hold up. I don't care if it is overrun with tourists as long as tourists are not being directly catered to

The culinary "institutions" of a city.

Think places like Bouillon Chartier in Paris or Katz Delicatessen in NYC.