Two major historical events dominated the period from 1929 to 1949: the Great Depression and World War II. When the stock market crashed in October of 1929, economic hardship struck many American citizens. Over the next 10 years the economy fell into a deep depression, alleviated only by vast government expenditures on wartime materials manufactured in the 1940s. Meanwhile, World War II dominated the political arena. Most significantly, the development and implementation of the nuclear bomb on the Japanese cities of Hiroshima and Nagasaki changed the practice of warfare and international diplomatic relations forever, ushering in the arms and space race with the Soviet Union, also known as the Cold War.