Most people will find that their investment objectives change throughout their lives. Capital appreciation may be more important for the young investor, but once she enters her golden years, that same investor may place a greater emphasis on gaining income. Whatever your objective, knowing what investment options are out there is key.

Furthermore, as most successful investors will tell you, diversification is king. A diversified portfolio not only reduces unwanted risk, but also contributes to a winning portfolio. And having a well-diversified portfolio doesn't necessarily mean just buying more than one stock; branching out into other areas of investment could be a viable alternative. Read on and learn about 20 investments that Investopedia feels every investor should know.