What is it about real estate that makes it a good investment?

Despite the crash of 2008 and 2009, real estate remains a solid investment over time. Why might this be the case? What is it about real estate that makes it a good investment? What kinds of real estate investment vehicles exist, and what are the characteristics of those vehicles? How do you, or could you, use real estate in your portfolio? Your 200 word answer should focus on selecting the most relevant factors and the investment potential of various types of real estate