High Quality Content by WIKIPEDIA articles! The Wall Street Crash of 1929 (October 1929), also known as the Great Crash, and the Stock Market Crash of 1929, was the most devastating stock market crash in the history of the United States, taking into consideration the full extent and duration of its fallout. The crash signaled the beginning of the 12-year Great Depression that affected all Western industrialized countries and that did not end in the United States until the onset of American mobilization for World War II at the end of 1941.