Story highlights

You may know about John Hancock's famously large signature or that Thomas Jefferson authored the document, but here are six facts you may not know about the Declaration.

1. The Declaration of Independence was not signed on July 4. 

Although July 4 is the day the United States celebrates independence, that was not the day the document was signed. The Continental Congress did adopt the Declaration on that day, but most delegates did not sign the document until August 2, 1776,according to the National Archives. New York delegates could not officially give their support until July 9, and the Congress didn't order that the official document be written on parchment until the 19th. Also, July 4 was not the day the founders expected to be remembered as Independence Day. July 2, the day the Continental Congress voted for independence, was thought to be the day of celebration, which was even noted by John Adams in his writings, according to the National Archives. 

2. There is more than one copy.

Even though most people who see the document see the original on display at the National Archives in Washington, D.C., hundreds more were printed. These copies are known as the "Dunlop broadsides", after the owner of the shop that printed them, John Dunlop. The copies were dispatched to the colonies to be read aloud for people who could not read. Of the hundreds printed, only 26 are known to have survived, including two which were found in the last 26 years. One was found in 1989 by a Philadelphia man hidden in a picture frame he bought at a flea market for $4 and the other was found in a box of papers at the British National Archives in 2009.

3. It started a riot.

When a Dunlop broadside was read by George Washington in New York City on July 9, 1776, the words so inspired the people listening that they started a riot. Later that day, they tore down a statue of George III, which was later melted and shaped into musket balls for the American army, according to the History Channel.

4. Jefferson and Adams died on the same day -- July 4

Thomas Jefferson and John Adams both died on the same day -- on July 4, 1826, 50 years after the Declaration's adoption, according to the National Archives. Adams assisted Jefferson in writing the declaration and also played a part in persuading the Congress to declare independence.

5. Reese Witherspoon: actor and Daughter of the Declaration?

Reese Witherspoon has said that she is a direct descendant of John Witherspoon, who signed the Declaration as a representative of New Jersey. However, her claim has never been proven.

6. A mark on the document is still an unsolved mystery.

A mystery about the document that still has yet to be solved is that a handprint appears on the bottom left corner. Although the origins of the mark are still unclear, its presence does not seem to surprise historians, since the document was rolled, put in bags and transported in wagons and ships. 

"It was terrible," said David Ward, senior historian at the National Portrait Gallery, told CNN's Chris Moody. "It was put in a burlap bag. They rolled it up all the time, which you're not supposed to do. It was exposed to light, it was exposed to smoke."

Protection of the document has of course ramped up significantly, now sealed in a titanium-and-aluminum frame with controlled humidity. During World War II, according to the National Archives, it was transported in 150 pounds of protective gear to Fort Knox, where it spent the remainder of the war.

Read the Declaration of Independence