July 4th commemorates the day the U.S. declared independence from the Kingdom of Great Britain. But what do you really know about the history of the holiday? Vince Gallagher has a crash course.

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UNITED STATES -- When you think of the Fourth of July, barbecues, flags, and fireworks may come to mind. But there's more to it than that.

After the legal separation of the thirteen colonies from Great Britain occurred on July 2, 1776, Congress drew up a Declaration of Independence, with Thomas Jefferson being the principal author. It was finally approved and on July 4, becoming the first "Independence Day." However, it wasn't entirely official until all 56 signatures were on the declaration. This took place on August 2, 1776.

Looking at a timeline, in 1777, residents of Philadelphia celebrated the first anniversary with music, parades, and yes…fireworks, kicking off a national tradition. The first public Fourth of July event at the White House occurred in 1804.

In 1870, Congress made Independence Day an unpaid holiday for federal employees. In 1938, it was changed to a paid holiday.

Then there are Presidential coincidences. Both John Adams and Thomas Jefferson, the only signers of the Declaration of Independence to later serve as President of the United States, died on the same day: July 4, 1826.

And of course there are celebrations on this day from barbecues to parades to fireworks. Red, white, and blue decorations are another are a common sight at get-togethers and this particular time happens to be one of the busiest travel periods of the year.