Your question contains a logical inconsistency. Obviously without safety, it wouldn't be safe.
But if you're asking if you should only invest your money in "safe" investments, that is certainly one way to invest your money. Understand that the greater the risk, that is the less security and safety, the greater the reward. So stocks, which are a risky investment as we've seen the last few years, also offer the greatest chance for large gains. Bonds offer a safer alternative but the rate of return is lower. Savings accounts, where your money is pretty much guaranteed to not lose money have a very low return.
So you really need to decide how much risk your willing to take in exchange for the chance to make more money.