15 March 1933: The Dow's best day ever

The New York Stock Exchange reopened after an 11-day shutdown during the banking crisis, and the Dow soared 15.34%, its biggest one-day percentage gain ever. President Roosevelt's bank holiday and his first fireside chat had restored some confidence. The Dow was still far below its 1929 peak, but the worst was over. The biggest rallies tend to come amid the worst gloom.

The lesson: Some of the best days in market history occur right in the middle of the worst periods.