The war ended on November 11, 1918, with the signing of the Armistice of Compiègne. The Treaty of Versailles, signed on June 28, 1919, imposed harsh penalties on Germany, including significant territorial losses and reparations.

The immediate cause of World War I was the assassination of Archduke Franz Ferdinand, the heir to the throne of Austria-Hungary, on June 28, 1914, in Sarajevo, Bosnia. The assassination was carried out by Gavrilo Princip, a Serbian nationalist who was a member of the Black Hand secret society.

World War I, also known as the Great War, was a global conflict that lasted from 1914 to 1918. It was one of the deadliest conflicts in history, involving many of the major powers of Europe and beyond. The war was fought between two main alliances: the Allies, which consisted of France, Britain, Russia, and the United States, among others; and the Central Powers, which included Germany, Austria-Hungary, and the Ottoman Empire.

In response to the assassination, Austria-Hungary issued an ultimatum to Serbia, which Serbia refused to comply with. Austria-Hungary then declared war on Serbia, followed by the declarations of war by Germany on Russia and France. Britain declared war on Germany on August 4, 1914, after Germany invaded neutral Belgium.