The immediate trigger for World War I was the assassination of Archduke Franz Ferdinand, heir to the throne of Austria-Hungary, on June 28, 1914, by a Serbian nationalist in Sarajevo, the provincial capital of Bosnia-Herzegovina (formally annexed by Austria-Hungary in 1908).
However, the roots of the war can be traced back to several factors that had been simmering for decades:
1. Nationalism: Rising nationalist sentiments and competition among European powers, particularly between Germany, France, Russia, and Austria-Hungary, created an atmosphere of tension and rivalry.
2. Imperialism: European powers were vying for control of colonies and resources in Africa, Asia, and the Middle East, which increased tensions and the risk of conflict.
3. Arms Race: There was a significant arms buildup and militarization by major European powers, fueled by mutual suspicion and a desire for military superiority.
4. Alliances: A complex system of alliances had formed among European countries, creating a tangled web of obligations and commitments that made it difficult to isolate a conflict.
5. Unresolved Tensions: Several longstanding territorial disputes and unresolved grievances between countries added to the tinderbox of tensions in Europe.
The assassination of Archduke Franz Ferdinand acted as the spark that ignited the powder keg of these underlying factors, leading to the outbreak of World War I on July 28, 1914.
World War 2:
The start of World War 2 can be mainly attributed to the following key factors:
1. Treaty of Versailles: The harsh terms imposed on Germany after World War I, particularly the Treaty of Versailles, created deep resentment and a desire for revenge among the German people.
2. Rise of Fascism: The emergence of fascist regimes in Europe, most notably Nazi Germany under Adolf Hitler, led to aggressive expansionist policies and a disregard for international norms.
3. Appeasing Hitler: The policy of appeasement adopted by Western powers, which involved concessions to Hitler in an attempt to avoid conflict, emboldened Germany and contributed to the outbreak of war.
4. Nazi Expansionism: Germany began a series of territorial annexations and military aggressions, including the occupation of the Rhineland, the annexation of Austria (Anschluss), and the invasion of Czechoslovakia.
5. Invasion of Poland: The culmination of Nazi expansionism came on September 1, 1939, when Germany invaded Poland, leading to the outbreak of World War II.
It's important to note that these are highly condensed explanations, and the start of both World Wars involved a complex interplay of historical, political, economic, and social factors.