Reality Studio is correct, if you're smart you can really do well leveraging. It's basically the same as pinball, you make smart purchases at below average house values where it cash flows, then if house values drop it won't matter because the rent is covering your payment anyways.
I'm not talking about buying Cali homes, I'm talking about areas where properties are $100k and under for the most part for single family homes or have smaller apartment complexes.
As far as 'no risk', what's riskier, letting your money getting devalued by inflation by 1%, or putting it the stock market where it may be volatile but overall will be up over the long term. Or buy a reit that pays 8%. Or buy someone else's mortgage and let them make payments to you. Or get into an accredited investor offering. Or buy a rental house. You don't have to leverage anything if you don't want, buy a rental house for 80k, rent for 1k a month, make $700 a month after taxes/insurance.
There are tons of options. Do whatever you're comfortable with.