I often run across old barbed wire fences on my hikes in CA, ID and MT. I often wonder who put it there and when. The stuff is rusted, but seem indestructible. I saw a fence line with five strands of barbed wire last week — an unusually high number of strands.
I used to see detectorists at the Lake Michigan shoreline. Based on what the inconsiderate pigs leave behind, I’d imagine there were a lot of screw-tops from beverages and such.