Would you really be liquidating all your holdings? Or, are you just looking to transfer it to something more stable and less likely to lose value? If the latter, CDs are a nice safe, boring choice. You won’t have immediate liquidity (and you probably wouldn’t if the former scenario was in play), and the interest rate probably won’t cover inflation (inflation is looking pretty high at this point). If you have a lot of time before retirement (or whatever use you’re looking for), you can try index funds. Another good bet would be annuities, but those aren’t insured usually, so there might be a problem if you have too many eggs in one basket. The guaranteed rate of returns are usually pretty good (I saw one at 6.5% recently).
If you think end of the banking system and worldwide systemic collapse is happening, then I suggest gold and jewels are probably the safest bet. If you think there will be some sort of economy, and you have time and like risk, buy real estate. A lot of people had made money off real estate in California during their many market crashes.