1870s

alt=|thumb|335x335px|From left to right, clockwise: Conflicts start to increase between the Second French Empire and the [[Kingdom of Prussia leading to the Franco-Prussian War in 1870; a fire in Chicago kills approximately 300 people and leaves about another 100,000 people homeless in 1871; Claude Monet's Impression, Sunrise is recognized as the source of inspiration for the Impressionist movement; The U.S. Army is defeated by Arapaho, Lakota and Northern Cheyenne tribes during the Battle of the Little Bighorn in 1876; Nicolaus Otto patents the first commercial four-stroke internal combustion engine; Queen Victoria is recognized as the "Empress of India" in the Royal Titles Act 1876; Emirate of Afghanistan forces defend against British Raj invaders in the Second Anglo-Afghan War; British Empire and Zulu Kingdom fighters engage in combat during the Anglo-Zulu War.]] The 1870s (pronounced "eighteen-seventies") was a decade of the Gregorian calendar that began on 1 January 1870, and ended on 31 December 1879.

The trends of the previous decade continued into this one, as great new empires, imperialism and militarism rose in Europe and Asia. The United States was recovering from the American Civil War, though the Reconstruction era introduced its own legacies of bitterness and racial segregation in the country. Germany unified as a nation in 1871 and became the German Empire. Changing social conditions led workforces to cooperate in the form of labor unions in order to demand better pay and working conditions, with strikes occurring worldwide in the later part of the decade and continuing until World War I. The decade was also a period of significant technological advancement; the phonograph, telephone, and electric light bulb were all invented during the 1870s, though it would take several more decades before they became household items.