I just noticed a "bridge" category. As I love old bridges..........:-)
The Thousand Island Parkway, constructed in the late 1930's, was a part of the main highway (2) between Toronto and Montreal. It was renumbered to highway 2S (Scenic) in 1947, then became a part of the 401 in the 50's and was intended to fulfill that role until local protest motivated the construction of a new route for the 401 north of this area. This was completed in 1968, at which time the designation 2S returned until the whole thing took on its current name when transferred to the St. Lawrence Parks Commission several years later. For anyone thinking the Government of Ontario has difficulty making decisions, this would seem to vindicate that line of reasoning for you.
Originally built as a four-lane main highway, the reversion back to "Scenic" and the construction of the 401-proper made this redundant, and two of the four lanes (the north/westbound pair) were converted into a bicycle/walking trail. This left some odd artifacts lying about, not the least of which is this set of twinned bridges completed in 1940. One is clearly maintained to highway standards, the other one, not so much. Not sure I have ever seen another example of twin bridges like this where one can see the difference routine maintenance can have.
Of particular note are the "Safety Barriers" on the side, morbidly shaped like tombstones as anyone having need of these safety devices would surely be killed on impacting one of them. Also of note is the now closed pedestrian walkway on the in-service bridge, made redundant by the fact its ENTIRE twin is now a pedestrian walkway.....