Our new ATC friend gave us a great tour... Wow, what a cool place!!!
Every area has its own specialty (for example, northern Ontario, or East/West), and the folks who work there focus specifically on traffic in that area, and become experts in that area.
In the section that deals with incoming traffic to YYZ from the east, we got to see how all traffic is funneled into a sort of digital "box" on the screen, oriented depending on the runway in use, from which they are handed over to the tower for arrivals. The people who work this area area also see GA traffic in the "practice area", and the ATC guy there told us horror stories of two targets he has often watched, both well within their legal rights, converge and just barely miss one another, due to not being in communication with Toronto Centre.
We got to see how radar coverage is affected by altitude, for example, how far away they can see our little Cessna 150s when we fly our cross-country easts, depending on how high or low we fly. In general, higher is better. (Though of course it takes forever for our little planes to climb to altitude!)
Visiting Toronto Centre was an eye-opening experience, and I feel like I have a little better understanding now, that will serve me well as a pilot.
We almost got to see the tower, too, but were late for a plane booking at CYTZ, so we had to go. Next time!