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If Groundspeak's Geocaching website had no specific rules regarding where you could hide a Geocache, meaning, as long as there was a physical container at the coordinates that a reviewer could reach out and touch, the cache would be published. Is there anywhere specific you would put a Geocache? (In this scenario the 161 metre rule still applies)
I myself would place one within the abandoned paper mill beside my town, the mill was partially demolished to remove the machinery but i'm sure there would be tons of amazing hiding spots for containers of all shapes and sizes. The Mill is still technically owned by a development company, so no caches can be placed (in fact, you can't even step foot on the property.), but it's fun to think about all the tiny nooks and crannies that the place is almost certainly littered with.