U.S.History: 1877-2008 By 296797 Period: 1776 to 1860 Early American history Period: 1860 to 1877 Civil War/Reconstruction Period: 1870 to 1900 The Gilded Age Period: 1890 to 1920 The Progressive Era Period: 1898 to 1910 Imperialism Period: 1914 to 1918 World War I Period: 1920 to 1929 Roaring Twenties Period: 1929 to 1930 Great Depression Period: 1935 to 1945 World war II 1940 United Nations formed Period: 1945 to 1960 Civil Rights era Period: 1945 to 1960 Early Cold war The action preventing the expansion of a hostile country or influence. Space Race, a competition between nations for in the weapons. 1947 Truman Doctrine 1947 22nd Amendment 1948 Berlin Airlift 1948 Marshall Plan 1949 NATO established 1951 Rosenbergs trial 1952 First h-bomb detonated by the United States Period: 1954 to 1976 Vietnam war 1955 Jonas Salk invents the Polio Vaccine 1957 USSR launches Sputnik Period: 1970 to 1991 end of the cold war Period: 1990 to 2008 1990s-21st century