1860s

thumb|335x335px|From top left, clockwise: Scottish physicist James Clerk Maxwell formulates the classical theory of [[electromagnetic radiation, bringing together for the first time electricity, magnetism, and light as different manifestations of the same phenomenon; the Meiji Restoration leads to enormous changes in Japan's political and social structure; the International Workingmen's Association is formed in 1864, aimed at uniting a variety of different left-wing socialist, communist and anarchist groups; the Battle of Avay, fought in 1868 during the Paraguayan War, the bloodiest inter-stat