US history: 1867-2007 By Emmanuel.Ware Period: 1776 to 1860 Early American history Period: 1860 to 1877 Civil War/Reconstruction Period: 1869 to 1869 transcontinental railroad completed Period: 1877 to 1900 The Gilded Age Period: 1890 to 1920 Progessive Era Period: 1898 to 1910 Imperialism Period: 1914 to 1918 World War I Period: 1920 to 1929 Roaring Twenties Period: 1929 to 1939 Great Depression Period: 1939 to 1945 World War II 1945 United Nations formed Period: 1945 to 1960 Early Cold War 1948 Berlin Airlift 1949 NATO Established 1950 Korean War begins Period: 1950 to 1970 Civil Rights Era 1951 Rosenbergs Trial 1952 First H bomb Detonated By the United States 1953 Korean War ended Period: 1954 to 1976 Vietnam War 1955 Jonas Salk invents the Polio Vaccine 1957 USSR launches Sputnik Period: 1970 to 1991 End of Cold war Period: 1990 to 2008 1990s-21st Century