S&P historical returns for 5 best periods
Graph source: Robert Shiller
Increase over previous 5 years: 170.8 percent
A booming economy and wild speculation pushed markets to record highs during the Roaring '20s. Investors borrowed to buy more stocks and pushed prices ever higher in 1928. The next year stocks did even better, but the infamous crash on Oct. 29, 1929, brought it all to an end, erasing $30 billion within a few days.