What's a well-known investment vehicle that has attracted hard-earned money for more than four decades? Here's a hint: It's all about retirement.Individual retirement accounts, or IRAs, account for a significant portion of Americans' retirement savings. Investors held approximately $9.2 trillion in IRAs at the end of March 2018, representing nearly one-third of retirement assets, according to the Investment Company Institute.If you're interested in opening an IRA, here's what you need to know.Continue reading