The twentieth century represented the crisis of European hegemony and the emergence of ideological competition as the defining feature of international politics. The First World War destroyed the Austro-Hungarian, Ottoman, Russian, and German empires, bankrupted Britain, and created the conditions for Bolshevik revolution. The interwar period witnessed failed attempts to reconstruct international order through the League of Nations, followed by the Great Depression's devastation of global trade and the rise of fascist, Nazi, and militarist challenges to the liberal international order. The Second World War completed Europe's self-destruction and established the United States and Soviet Union as superpowers whose ideological antagonism would structure global politics for four decades.
