Historically, no portfolio was complete without a material allocation to real estate. Consistently high real returns and low correlations to stocks and bonds made it easy to overlook the out-of-whack fundamentals that ultimately led to an unprecedented collapse. But when real estate markets got a reality check in late 2008, many investors swore off the asset class for good. Or so they thought.

After losing their shirts in real estate investments during the financial crisis, many investors washed their hands (and their portfolios) of REITs, unable to tolerate such extreme volatility and unwilling to accept the downside ramifications of risky assets. But investors who were able to spot the bottom of the real estate market in the U.S. have been handsomely rewarded, and now many are beginning to consider a more significant allocation to this asset class. The ETF boom has presented dozens of options for investors looking to add real estate to their portfolios, ranging from broad-based U.S. funds to more targeted ETFs to strictly international real estate exposure.