I stand corrected. But compared to other cities of relative age, I'd say Toronto has done a poor job maintaining its older properties IMO.
It hasn't done a *great* job, and many older buildings were demolished in the 50s-60s in the name of urban renewal. But there are plenty of gems out there if you know where to look. It's hard to look for "monuments" that define the city, in that Toronto really didn't do anything truly "fantastic" until the mid-century, starting with City Hall, and continuing with TD Centre and finally reaching its zenith with the CN Tower. Toronto truly is a modern city, which much newer development than other big city counterparts such as NYC, Chicago, etc.