The American Revolution was one of the most significant events in world history because it created a "new thing called a citizen," iconic filmmaker Ken Burns told CBS News, as the nation celebrates the Fourth of July exactly one year before its 250th birthday.

As the U.S. celebrates 249 years since the signing of the Declaration of Independence, CBS Evening News co-anchor John Dickerson spoke with documentarian Ken Burns about his new film on the American Revolution and the importance of telling the story of American history.