What people don't know about the 4th of July, is what happened on the day before, July 3.
The Declaration of Independence
As America observes the 4th of July as its Independence Holiday, really it was a couple days earlier on July 2, that the Second Continental Congress approved its Resolution of Independence from Britain. John Adams himself opined that July 2nd, and not the 4th, would be the date memorialized thereafter in America. He may have been off by two days, but the idea was clear: July 2nd and 3rd were the monumental days to be remembered in the USA.