The years leading up to the declaration of war between the Axis and Allied powers in 1939 were tumultuous times for people across the globe. The Great Depression had started a decade before, leaving much of the world unemployed and desperate. Nationalism was sweeping through Germany, and it chafed against the punitive measures of the Versailles Treaty that had ended World War I. China and the Empire of Japan had been at war since Japanese troops invaded Manchuria in 1931. Germany, Italy, and Japan were testing the newly founded League of Nations with multiple invasions and occupations of nearby countries, and felt emboldened when they encountered no meaningful consequences. The Spanish Civil War broke out in 1936, becoming a rehearsal of sorts for the upcoming World War -- Germany and Italy supported the nationalist rebels led by General Francisco Franco, and some 40,000 foreign nationals traveled to Spain to fight in what they saw as the larger war against fascism. In the last few pre-war years, Nazi Germany blazed the path to conflict -- rearming, signing a non-aggression treaty with the USSR, annexing Austria, and invading Czechoslovakia. Meanwhile, the United States passed several Neutrality Acts, trying to avoid foreign entanglements as it reeled from the Depression and the Dust Bowl years. Below is a glimpse of just some of these events leading up to World War II. Adolf Hitler, age 35, on his release from Landesberg Prison, on December 20, 1924. Hitler had been convicted of treason for his role in an attempted coup in 1923 called the Beer Hall Putsch. This photograph was taken shortly after he finished dictating "Mein Kampf" to deputy Rudolf Hess. Eight years later, Hitler would be sworn in as Chancellor of Germany, in 1933. apanese soldiers involved in street fighting in Shanghai, China in 1937. The battle of Shanghai lasted from August through November of 1937, eventually involving nearly one million troops. In the end, Shanghai fell to the Japanese, after over 150,000 casualties combined. Solemnly promising the nation his utmost effort to keep the country neutral, U.S. President Franklin D. Roosevelt is shown as he addressed the nation by radio from the White House in Washington, Sept. 3, 1939. In the years leading up to the war, the U.S. Congress passed several Neutrality Acts, pledging to stay (officially) out of the conflict.