I love this kind of stuff. Excellent idea.
I don't have any pictures, but when I was in junior high (about ten years ago) me and some buddies came across some this boarded up concrete building in the Whitemud ravine near Twin Brooks while searching for a loaction to host a bush party.
It was so weird to see because it was fairly recent. Facing the river there was a huge window, but it had giant metal plates to block anybody from going inside. The door was on the other side of the house and it had a trench like entrance. Nothing else was visible as it was a dome structure that was covered in soil.
I'm pretty sure it's gone now, but the path leading to it is still there. If you look near the yellow arrow, there is a path leading from near the end of the cul-de-sac that has a switch back.
Does anybody have any idea what this was? I always assumed it was just a house that the landowner built before he sold off the surrounding farm land...but like I said, this stuff fascinates me.
Growing up in Newfoundland, abandoned stuff like this was all over. Never knowing all the answers would drive me crazy.