Basic United States History Dates By gwilliams Aug 20, 1492 Columbus sails the ocean blue Aug 20, 1607 Jamestown Aug 20, 1776 Declaration of Independence Aug 20, 1789 Constitution Aug 20, 1803 Louisiana Purchase Aug 20, 1812 War of 1812 Period: Aug 20, 1861 to Aug 20, 1865 Civil War Period: Aug 20, 1917 to Aug 20, 1918 U.S. involvment in World War I Aug 20, 1929 Stock Market Crash and the beginning of the Great Depression Period: Aug 20, 1941 to Aug 20, 1945 U.S. involvement in World War II Period: Aug 20, 1945 to Aug 20, 1989 Cold War Period: Aug 20, 1950 to Aug 20, 1953 Korean War Period: Aug 20, 1965 to Aug 20, 1973 Vietnam War Aug 20, 1991 Gulf War Aug 20, 2001 September 11 Aug 20, 2003 US invasion of Iraq