World War I lasted four years, three months and two weeks, beginning in July 1914 and ending in November 1918. The conflict started with Austria-Hungary declaring war on Serbia in retaliation for the assassination of Arc... More » History Modern History World War 1

World War II lasted approximately six years. The war began with the Nazi invasion of Poland on Sept. 1, 1939, and ended with Japan's surrender in August 1945. More » History Modern History World War 2

World War II lasted six years in Europe and eight years in the Pacific. American involvement in the war lasted four years from December 1941, when Japan attacked Pearl Harbor, to 1945, when both Japan and Germany were de... More »

World War I, which started in July 1914 and ended Nov. 11, 1918, was responsible for more than 17 million casualties, approximately 100,000 of which were troops from the United States. Causes of World War I include mutua... More » History Modern History World War 1

Although the assassination of Austrian Archduke Franz Ferdinand is cited as the main cause that thrust the world into war, many causes and events led up to World War I. Some of the secondary causes include the mutual def... More »

The Triple Entente was an alliance between Russia, the United Kingdom and France in the years leading up to World War I. It was made official after the U.K. and Russia signed the Anglo-Russian Entente on August 31, 1907 ... More » History Modern History World War 1

World War I was considered a total war because all of the population of the main nations involved were called into service in one way or another. Even women, who typically were not involved in war, were responsible for g... More »