Moments in time
Although each year of American history is important, there seems to be three sets of 20 year spans which have seen phenominal historical events and changes in the U.S.A. These "sets" of decades are exactly 100 years apart!
The years 1770-1790 witnessed protests against British rule, the birth of a new nation, a revolution; which lasted eight years, plus the writings of the consistition, election of the first president and admission of the original 13 colonies ot the Union.
Exactly 100 years later, the same span of years saw crucial developments in the U.S.A. The vivil war was over but the years 1870-1890 saw the critical developments of reconstruction, the arrival of railroads in towns previously not linked, new inventions like the telephone, photograph and light bulb, and the end of the wars with the Native Americans and U.S. Army.
One hundred years later the U.S. had to span from 1970 to 1990which saw the end of controversial conflicts, cold and hot political and constitutional crises which tested the republic's duration, the devlopment of technology like PC's, faxes, VCR's, CD's, cell phones, and the celebration of our bicentennial.
The study of all American history is fascinating but if you really want to hone in on some important stuff, read about the periods or 1770-1790, 1870-1890 and 1970-1990.
David Shipp, Nevada