World War II
For many European and Asian countries, World War II was unquestionably the most important event of the twentieth century, both in general and in its economic aspects. For the United States, it was also very important, although many economists and economic historians view the Great Depression as an event of equal or greater economic importance. The war engaged most of the world’s countries and all of its great powers. It lasted four to six years, depending on the country, and arguably several years longer for Japan and China, whose engagement some historians date from Japan’s initiation of war against China in 1937 or its invasion of Manchuria in 1931. The war ended in May 1945 in Europe, in August 1945 in Asia.