US history 1887-2008 By 230380 Period: 1776 to 1860 Early American History Period: 1860 to 1877 Civil War/Reconstruction Period: 1877 to 1900 The Gilded Age Period: 1890 to 1920 The Progressive Era Period: 1898 to 1910 Imperialism Period: 1914 to 1918 World War I 1945 United Nations formed Period: 1945 to 1960 Early Cold War Containment Arms Race/Space Race The Union of Soviet Socialists Republics Communism Domino Theory 1947 Truman Doctrine 1948 Berlin Airlift 1948 Marshall Plan 1949 NATO established 1950 1950-1953 Korean War Period: 1950 to 1970 Civil Rights Era 1951 Rosenberg Trials 1951 22nd Amendment 1952 First H-Bomb detonated by the United States 1955 Jonas Salk invents the Polio Vaccine 1957 USSR launches Sputnik 1962 Cuban Missile Crisis 1965 Medicare and Medicaid established 1968 Tet Offensive Period: 1970 to 1991 End Of Cold War 1971 Pentagon Papers leaked 1975 Fall of Saigon, marks the end of the Vietnam War Period: 1990 to 2008 1990s-21st century