Alternative assets are investments that fall outside the traditional categories of stocks, bonds, and cash. They include items like real estate, commodities, private equity, hedge funds, and collectibles such as art or vintage cars. These assets can provide diversification in an investment portfolio, potentially reducing risk and enhancing returns. Investing in alternative assets often requires specialized knowledge and may involve higher fees and less liquidity compared to traditional investments. However, they can offer unique opportunities for growth and may perform differently in various market conditions, making them appealing to some investors looking for non-correlated returns.