[Matt Ciprietti]

One bit of context that's missing - "The Six" or "The 6ix" (or whatever) to refer to Toronto actually IS based on an area code as well - 416, Toronto's oldest and biggest one (since there are several now). As was already mentioned, Drake kind of took it and ran with it.

And yup, that's the CN Tower. It was the world's tallest freestanding structure for about 30 years, only beaten in the last 10 years or so. It's basically a symbol for Toronto like how any showpiece/record-breaking building would be in another city.