The nineteenth century was a story of nation-building, industrial might, and imperial ambition. In the United States, the doctrine of Manifest Destiny drove westward expansion, but it also brought tragedy, most infamously the Trail of Tears in the 1830s, when Native American tribes were forcibly relocated and thousands died. These tensions culminated in the Civil War (1861–1865), fought under President Abraham Lincoln. His Emancipation Proclamation of 1863 declared enslaved people in Confederate states free, and the Thirteenth Amendment formally abolished slavery in 1865. The subsequent Reconstruction period (1865–1877) attempted to reintegrate the South but ultimately left many of its promises unfulfilled.
In Europe, the impulse toward unification produced two new great powers. Otto von Bismarck led the unification of Germany in 1871 under Prussian leadership, while a more complex coalition of Giuseppe Garibaldi, Camillo di Cavour, and King Victor Emmanuel II completed Italian unification the same year. Industrial and military confidence pushed European states outward: the Scramble for Africa between roughly 1881 and 1914 saw the continent carved up by colonial powers, a process formalized at the Berlin Conference of 1884–1885. Meanwhile, new ideas spread through Europe as Karl Marx and Friedrich Engels published The Communist Manifesto in 1848, igniting a political movement that would shape the coming century.
Asia also experienced forced and voluntary transformations. The Opium Wars (1839–1842 and 1856–1860) saw Britain compel China to accept the opium trade, ending with the Treaty of Nanking in 1842, which ceded Hong Kong to Britain. In 1857, a vast uprising against British East India Company rule in India paved the way for direct British rule. Japan responded differently: the Meiji Restoration of 1868 restored imperial authority and launched rapid modernization. Technological landmarks marked the era, including the opening of the Suez Canal in 1869, the unveiling of the Statue of Liberty in 1886, the completion of the Eiffel Tower in 1889, and the Panama Canal in 1914. The United States, fresh from the Spanish-American War of 1898, gained Puerto Rico, Guam, and the Philippines, while foreign powers joined to crush the Boxer Rebellion in China (1899–1901). Russia, meanwhile, convulsed in the failed 1905 Revolution, which led to the creation of an elected Duma.