18641920

1864–1920 is not a formal historical era, but a convenient label for a span that covers the late 19th and early 20th centuries, during which rapid industrialization, urbanization, and imperial expansion helped reshape economies, societies, and politics worldwide. The period is sometimes denoted simply as 1864–1920 to reflect its broad temporal scope.

Across continents, the era witnessed fundamental political and social changes. The year 1864 saw the founding of the International Workingmen's Association, reflecting the rise of organized labor movements. The late 19th century saw the unifications of Germany (1871) and Italy (completed by the 1870s). European powers intensified imperial competition in Africa and Asia—the Scramble for Africa (1880s–1914)—and the global expansion of railways, telegraphs, and industrial production.

World events dominated the first decades of the 20th century. World War I (1914–1918) remade borders and power relations; the Russian Revolution of 1917 introduced a new ideological force; the 1918–1919 influenza pandemic affected populations worldwide. The postwar period culminated in the Treaty of Versailles (1919) and the creation of the League of Nations in 1920, signaling a move toward formal mechanisms for international cooperation.

The 1864–1920 span thus marks a transition from earlier empires to a modern international order, with rising nationalism, socialism, and liberal constitutionalism competing for influence. It laid groundwork for interwar politics, decolonization movements, and ongoing debates about governance, technology, and global connectivity.