This has multiple things I'd never seen, including two gallons of mercury poured into a tub in someone's backyard. I wonder what he did with it them

https://www.wimp.com/floating-an-anvil-on-liquid-mercury/

Odd physics huh?

I've seen other videos from this guys channel.  He inherited an old mine.  Some of the mercury he has is left over from the mining processes and then he bought some more from people he knew were also in the mining business.  He handles the stuff all the time, sometimes even exposes his skin directly.  He claims that he gets his blood mercury levels tested often.