That was an ugly time in Germany. So basically after the first World War France threw a bitch fit that French army wasn't as great as the Germany army, so they wanted to blame the Germans for starting a horrible war when in actuality it was actually the Austro-Hungarian Empire and Russia starting the whole conflict. Anyway the League of Nations all agreed that Germany had to pay war reparations, shrink it military, loss it's possessions, and they couldn't have a real navy. Anyway France wanted it's money now kept pressuring Germany into repaying them quicker. So some idiot in the economics department decides that printing more Marks was a good idea, however whoever they were they forgot to factor in consequences of inflation. So Germany went into further debt, unable to repay France, and it's currency was useless which threw all of Western Europe into a depression. Also as a result the depression lead to a political mess between conservative and liberal factions in Germany which lead to the raise of national socialistsm.
Meanwhile in the United States the Stock Market became really popular and anyway who is anyone could buy and sell stocks at the stock market. Before, wallstreet was just mostly gamblers and rich business men investing into companies, but that changed in the 1920's. So people started go to the banks to get a loan, from there they used their loan money to invest in a stock or create a company. Everything was good for a while until the banks wanted to get their loans back and eventually the stock prices crashed and people were stuck with having a huge debt to pay off. Unable to receive the money owed from the investors, the banks started to suck money for it's more responsible customers and businesses which brought them into debt too. So the banks were then going to shut down too, so everyone raced to withdrawal their money which caused almost every bank to go out of business.
So not that you care, but now you know.