July 4, 1776 - July 4, 2015: 239 Years for a Young Democracy

That image and a lot more in between led to this and much more history since:

The American Revolution (1775-1783) is also known as the American Revolutionary War and the U.S. War of Independence. 

The conflict arose from growing tensions between residents of Great Britain’s 13 North American colonies and the colonial government, which represented the British crown. Skirmishes between British troops and colonial militiamen in Lexington and Concord in April 1775 kicked off the armed conflict, and by the following summer, the rebels were waging a full-scale war for their independence.

France entered the American Revolution on the side of the colonists in 1778, turning what had essentially been a civil war into an international conflict. After French assistance helped the Continental Army force the British surrender at Yorktown, Virginia, in 1781, the Americans had effectively won their independence, though fighting would not formally end until 1783. 

By June 1776, with the Revolutionary War in full swing, a growing majority of the colonists had come to favor independence from Britain.

On July 4, 1776 the Continental Congress voted to adopt the Declaration of Independence, drafted by a five-man committee including Benjamin Franklin and John Adams but written mainly by Thomas Jefferson (later 3rd President of the United States under the Constitution which would be ratified on June 21, 1788 (official date). 

That all became effective when Geo. Washington was sworn in as the First President of the United States of America on April 30, 1789, and in the eyes of the world ever since we became and are The United States of America.