Major Causes and Far-Reaching Consequences of World War I and World War II

Abstract

The First and Second World Wars were pivotal events of the twentieth century that transformed the course of global history through their far-reaching causes and consequences. World War I (1914–1918) stemmed from militarism, imperial rivalries, nationalism, and the entangled alliance system, triggered by the assassination of Archduke Franz Ferdinand, and it resulted in the collapse of major empires and the harsh Treaty of Versailles. The interwar period witnessed economic depression and the rise of extremist ideologies, which set the stage for World War II (1939–1945), initiated by Germany’s invasion of Poland and driven by fascist expansionism and the failure of collective security. Both wars caused massive loss of life, economic devastation, and political upheaval, but also led to the emergence of the United Nations, decolonization movements, and the Cold War rivalry. Collectively, their impact redefined international relations and shaped the modern geopolitical order.