The Great Seal of the United States which you'll find on the back of every one-dollar bill, is our nation's official emblem. Adopted on June 20, 1782, it's full of symbols that have specific meanings about values the Founders wanted to pass on to each generation.
The front of the Great Seal beats the coat of arms of the United States, showing an American bald eagle with a shield on its breast. The shield contains thirteen vertical red and white stripes, representing the thirteen orginal states. The eagle holds an olive branch with thirteen leaves and thirteen olives in its right talon, symbolizing strength in peace. It hold thirteen arrows in its left talon, meaning strength during war. The eagle faces the olive branch to show Americans prefer peace.
In its beak the eagle holds a scroll inscribed with the Latin motto E Pluribus Unum ("Out of Many, One"). The motto refers to the fact that the U.S. is one nation formed by several states.
Above the eagle's head is cloud surrounding a constellation of thirteen stars. The constellation breaking through the cloud symbolizes the United States taking its place among the other nations.
The red in the Great Seal symbolizes hardiness and valor. The white stands for purity and innocence; and the blue represents vigilance, perseverance, and justice.
(The American Patriot's Almanac)