Where is the safest place you could hide a phylactery in the real world?

I was having some shower thoughts and fantasizing if I could gain the power of a lich and could make a phylactery, where would be the best place to keep it in the real world? Can't be anywhere you cant exist like the bottom of the ocean as you need to respawn at it. Perhaps I was a billionaire and built a secret bunker in a mountainside. Or deep underground in a single room with a ladder out to a fake boulder.

Does anyone have any good/creative ideas?

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