So the last two were relatively easy - this next one you can't drive up to. There is a parking lot within walking distance, but that's about it.
What we're looking for is some elevated mountain bike trails in Calgary similar to this...
How safe the ones I've seen are is beyond me as I've never ridden on this kind of stuff, but there are a few sets of these carefully hidden away in a public park in Calgary and for starters, you can cross COP off of the list. Whomever built these had to hike all the stuff in over a good distance and would've had to probably have to have done everything in a rather clandestine fashion and I'm not even sure how extensive they are.
No clues to start as some of you are mountain bikers and may very well know where these elevated trails are.