The outbreak of world war was a traumatic, disillusioning event, particularly for those who had committed themselves to notions of progress and advancement in human affairs. Its scale exceeded that of any previous world war in terms of death and destruction, and it left a mark from which the continent of Europe never fully recovered.

Countries spent huge sums on building massive militaries, creating tension and rivalry. The assassination of Archduke Ferdinand in Sarajevo by Gavrilo Princip, a member of the Serbian nationalist terrorist group Black Hand, triggered hostilities. The resulting domino effect of war declarations set in motion a series of military miscalculations that led to the great war.

At first, most people greeted the outbreak of war with confidence and jubilation. Many believed their country’s side would be victorious within a few months. They saw the war either as a defensive struggle for national survival or idealistically, as one for upholding right against might and the sanctity of treaties and international morality.

The Allies quickly moved to clear the Axis powers from Europe. The invasion of Sicily prompted Benito Mussolini to surrender. Bitter jungle fighting earned the Allies a major victory in Burma. The U.S. smuggled Vladimir Lenin back into Russia to spur mass strikes. By the end of the war, millions of soldiers had been killed and many more had been displaced from their homes. The Allies had won total victory over Germany and Japan, but the war had unleashed a series of unresolved political, social, and economic problems that eventually brought the Western democracies into a confrontation with the Soviet Union under Stalin.