The October 1929 Wall Street Crash was a stock market crash in the United States signaling the beginning of the 10-year Great Depression that affected all Western industrialized countries and continued in the United States until 1947.
This was quoted by Stresemann about Germany's economic condition before the Wall Street Crash:

"The economic position is only flourishing on the surface. Germnay is in fact dancing on a volcano. If the short-term credits are calle in, a large section of our economy would collapse."
And it did.

HOW THE WALL STREET CRASH PROVIDED THE ECONOMIC CONDITION FOR HITLER TO RISE TO POWER
The Weimar Republic was devastated by the Wall Street crash and the Great Depression that followed. The Crash severely impacted the American economy, but because the US had propped the Weimar Republic(which was dependent on foreign economies and markets) with huge loans in 1924 (Dawes Plan) and in 1929 (Young Plan), the American economy impacted Weimar's economy severely as well. The Dawes and Young Plan had loaned Weimar money to prop up the country's economy, especially after the experiences of Germany's hyperinflation in 1923, the U.S demanded for a return of these loans after the Wall Street Crash to assist her faltering economy. After the Wall Street Crash, the U.S only gave Germany 90 days to start repaying all the loans that were lent to her. Thus, an impoverished Weimar Germany was effectively bankrupt by the end of 1929 and incapable of paying back any reparations and loans.
Companies throughout Germany went bankrupt and workers were laid of in the millions. Thus, the instability of the Weimar allowed Hitler to rise to power. The economic despair translated into the votes for the political extremes as the people of Germany search for another alternative to the Weimar. In the 1930 Reichstag election, the Nazis gained 143 seats. In July 1932 Reichstag election, the Nazis gained 230 seats making them the largest party in the Reichstag. The leg of the stool the Stock Market Crash increased were the people that would benefit from the Nazis proposed policies for Germany in taking it out of debt and away from the instability of the Weimar.