If you are seeking diversification outside of the US, you could take a look at well diversified international index mutual funds. These would be well diversified funds invested in foreign stocks & bonds. I'm not meaning trading in foreign currencies agains the USdollar, though international mutual funds will have volatility due to currency fluctuations.
If you mean you want to move US dollars into another foreign currency, you can open a foreign currency account. Which one, I have no idea. If the US economy falls apart, it is likely to have an impact on all world economies. BTW, the US dollar is still considered to be among the most stable currencies in the world. A google search says the Swiss franc is among the safest currency because of their neutrality, strong monetary policy, and low debt levels.
I'm not an expert and avoid trading in bullion. It seems like right now you would be buying high. The pundits say while it is a good hedge against inflation it can also be volatile and not appreciate when the market is strong. Gold also does not generate any income. The hope is for price appreciation. If you look at the data, the market has significantly outperformed gold & silver price appreciation over the long term.
Real estate, especially income generating real estate, has always been a good long term investment and has tax shelter opportunities.
I'm staying fully invested with about 20% in international equities and bonds. I want to be in the market to take advantage when upturns happen.
Of course, my comments are worth about as much as you paid for them.