landscapes are often places where people lose things, lost in the tall grass. People also sometimes dispose of things that are otherwise hard to get rid of in the landscape, like cans of old gasoline. It's pretty common for people to dig a big hole and throw in whatever garbage they have lying around, sometimes burning it before it goes in. Blue corrosion on punctured batteries. Sometimes people bury the evidence of a crime in the garden, like a pistol under the boxwood. When I'm gardening I never know just what my shovel might turn up, but it's always a treat to find a marble, the unbiodegradable marker for obscure games of yesteryear.