Independence Day is a hallmark of the American experience. It is remembered as the day America's founding document, the Declaration of Independence, was signed by the Founding Fathers on July 4, 1776.
As many things prescribed to American antiquity -- including Paul Revere's ride and Betsy Ross sewing the first flag -- that's not completely accurate. The Declaration of Independence was actually signed on August 2, 1776, and the Continental Congress declared independence on July 2, 1776.