The large agricultural farms of downtown Toronto grow tons and tons of wholesome wheat and that wheat has to be stored somewhere before it is made into Tims bagels and donuts. And I think that the silos that remain along the shores of Lake Ontario is where all the Toronto wheat goes. Sometimes it is difficult to see the farms but I believe that to save precious land for relatively unimportant roadways, the farms are placed on many of the downtown buildings. I often see trees along the edge of the roofline to help the farmer from driving their combine over the edge of the building. I will have to try the CN Tower EdgeWalk to see if I can see the farms and prove my hypothesis.
My initial theory about the silos was that they held nuclear weapons, but in 1983 Toronto became a nuclear weapons-free zone.