U.S. Constitution Takes Effect
The new U.S. Constitution took effect on this day, as the first Congress was seated. The United States is today the oldest continuously functioning constitutional democracy in the world. Constitution Day is celebrated on September 17th every year to mark the day the members of the Continental Congress agreed on the final version of the Constitution (go to September 17, 1787).
See an original copy of the Constitution at the Library of Congress: http://www.wdl.org/en/item/2708/
Learn more: Amar Akhil Reed, America’s Constitution: A Biography (2005)