A world war is a global conflict, involving multiple major nations and potentially touching many others in ways large and small. It features the use of mass armies and a wide range of weaponry, including airships known as zeppelins, and the destruction or displacement of whole groups of people. In addition to the carnage on the battlefield, world wars also involve diplomatic maneuvering and a race to find a way to avoid a clash of civilizations.

The first world war raged from 1914 to 1918 and was the largest military conflict in history, killing more than nine million soldiers and an estimated twenty million civilians. It introduced the world to such innovations as trench warfare and lethal new weapons as poison gas. It also ended the shattered Austro-Hungarian, Russian and Ottoman empires and created the modern map of Europe. But it did not bring peace, as resentment of the onerous terms of the Treaty of Versailles sparked Adolf Hitler’s rise to power in Germany.

Other primary causes of the war included Nazi Germany’s ideological aims, which Beiriger notes involved Antisemitism and unification of all Germans in a nation state along with acquisition of “living space” for agrarian settlers; Imperial Japan’s desire to acquire ports that allowed its navy and merchant ships access to the Pacific; and Fascist Italy’s aggression against Ethiopia. After Germany’s sinking of the passenger ship Lusitania tipped public opinion in favor of war, the US entered the fray.