The global conflict that marked the rise of authoritarian regimes in Europe was World War I. The war's devastating impact led to widespread social, political, and economic upheaval across the continent. In the aftermath of the war, numerous nations faced instability, economic hardship, and disillusionment with democratic processes. This turmoil provided fertile ground for radical ideologies, including fascism and communism, to take root. Authoritarian leaders like Adolf Hitler in Germany and Benito Mussolini in Italy exploited these circumstances, promising national revival and stability in exchange for popular support. Their rise transformed European politics and led to catastrophic consequences during World War II.