Final answer:
The Great Depression, which began with the 1929 stock market crash, caused worldwide economic collapse, due to a mix of factors, including demand for loan repayments by U.S. banks, international trade reduction, and protective tariffs. These contributed to a 15 percent global GDP decrease and widespread unemployment.
Step-by-step explanation:
The international economy witnessed a severe collapse during the Great Depression, which began with a drastic stock market crash on October 24, 1929. This economic downturn led to a global GDP decrease of 15 percent between 1929 and 1932, as trade plunged and banks called in international loans. Several contributing factors such as the overvalued stock market, protective tariffs like the Hawley-Smoot Tariff Act, and austerity policies led to widespread unemployment and poverty, with worldwide industrial output, particularly in Germany, dropping by nearly 50%. The lack of economic stability and foreign trade reduction during this period had profound impacts, with the Depression lasting throughout the 1930s until the economic stimulation of World War II.