I believe there's a whole bunch of people who have been owning Uluru for quite a while, now. They're the ones who have stopped people climbing all over it. Presumably it's rude to climb on a pet rock.
Does pet concrete count? I have a lump of pet concrete from when my office building of many years was bulldozed last year. Nothing wrong with the building, it was torn down because of the oil downturn in Aberdeen and to avoid business rates on an empty building after the company I contracted at relocated. :(