During the 1929 Wall Street Crash, October 28 was known as Black Monday.
The Dow Jones Industrial Average fell 38.33 points, or about 13%, on October 28, 1929. The next day, October 29, brought an even larger percentage decline and became known as Black Tuesday. Together, these sessions intensified the market panic that followed weeks of falling prices.
Black Monday is sometimes confused with Black Tuesday because both occurred during the same historic crash. Black Thursday, October 24, marked the first major panic-selling session, but the market did not reach its most dramatic two-day collapse until the following Monday and Tuesday.
The crash did not by itself cause every hardship of the Great Depression, but it severely damaged investor confidence and exposed weaknesses created by speculation, margin buying, and excessive optimism. The Dow would not recover its September 1929 peak until 1954.