How did World War I turn into a worldwide conflict by 1917?

World War I turned into a worldwide conflict by 1917 due to several key events and factors:

1. Assassination of Archduke Franz Ferdinand (1914): The war began as a regional conflict in Europe when Gavrilo Princip, a Serbian nationalist, assassinated the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand. This event triggered a series of diplomatic crises, leading to the outbreak of war.

2. Alliance System: The complex system of alliances between different countries also played a significant role. The Central Powers (Germany, Austria-Hungary, and Italy) and the Allies (France, Russia, and the United Kingdom) were the two main alliances. When one country was attacked, its allies