Free things to do in less than 7 hours?

I'm going to be in Toronto for immigration medical and only have about 7 hours (12-7pm) to kill before I gotta head back to my province. Now, I am extremely broke and can't afford things like the museum or restaurants sadly so I'm hoping for some cool architecture or sights to see while I'm here! Area I'm mostly going to be around is close to Cedarvale Park, so that area or closer to the major airport would be nice but I'm open to a little adventure. I wanna check out the public transportation as well since I've never been on a subway, so bonus if the subway goes by these spots. Thank you! I'm so excited to see what little i can in this city!