It may seem like a long time ago, but the epic stock market meltdown of half a decade ago is again worth pondering.

From around 1,300 in August 2008, the S&P 500 Index plummeted to 1,100 by late September and below 900 by the end of November. By the time we hit bottom in March 2009, the index had tumbled below the 700 mark. A nearly 50% plunge in just seven months is virtually unprecedented.

Now, with the S&P back up to around 1,800, we've seen a five-year rebound that should make us all quite thankful. This year has been especially fruitful, as the S&P 500 has tacked on more value this year (on the basis of market cap) than in any year in its history. The market hasn't even needed any breather this year on its path to record heights.