World War I (WWI) from 1914-1918 was known as the Great War; it was also called "the war to end all wars". Between 1914 and 1918, over 21 million soldiers and civilians died. Even more people were seriously wounded or disabled in the conflict. Over the next few days we will look at how World War 1 began. Historians point to four long-term causes of World War I: alliances, nationalism, militarism, and imperialism. Each cause will be discussed in more depth. The U.S. resisted physical involvement in WWI until 1917. We will evaluate how U.S. policy, under the leadership of President Woodrow Wilson, changes regarding WWI.