If what you’re looking at is fiat, maybe you should go for Euro and Yuan, both are among the top currencies in the world, but the US dollar is still the most powerful currency.

As for being safe, I don’t think anything is really safe, if you have cash stored up, it’s not really safe and the same thing with gold. Bitcoin seems to be a bit more safe if stored online, but if you store it in your computer or ledger or flash drive, you can still lose it if you’re not careful and when it gets to the hand of someone else that knows how to works they can pull your money from it. But BITCOIN is a good choice.