World War I
World War I (often abbreviated WWI) was a global war mainly centered in Europe but involving some of the colonies of the belligerent countries in Africa and Asia that began on 28 July 1914 and lasted until 11 November 1918. It was first called the World War or the Great War. But after the start of World War II in 1939, it was called First World War or World War I thereafter.
It involved all the world's great powers grouped in two opposing alliances: the Allies, initially the Triple Entente of the United Kingdom, France and Russia versus the Central Powers, led by the Triple Alliance gathering Germany, Austria-Hungary, and Italy (though later Italy entered the war on the side of the Triple Entente).
Both the German and Russian Empires suffered revolutions during the war and signed unfavorable treaties ending their involvement, resulting in much loss of territory. The Austro-Hungarian and Ottoman Empires collapsed entirely, breaking up near the end of the war.
The Versailles Treaty, which formally ended the war between Germany and most of the Allies, imposed punishing conditions on the rump state, some of which were blamed for setting the stage for the rise to power of Adolph Hitler and the Nazi Party.
This "war to end all wars" turned out to be only the beginning of massive amounts of suffering, death, and disease that wracked the globe during the 20th Century. When people question the goodness of God, based on all the suffering in the world, WWI is often at the root of their complaints.