Today, the flag of the United States is made up of thirteen alternating red and white stripes that represent the original thirteen colonies with fifty white stars on a blue background representing the fifty states. The colors of the flag are also symbolic. Blue is the color of perseverance, vigilance, and justice. White represents purity and red symbolizes valor. The basic design of the flag was established June 14, 1777 when the Continental Congress enacted the first Flag Act. The act called for the official flag to be "thirteen stripes, alternate red and white; that the union be thirteen stars, white in a blue field, representing a new constellation."

Over the years, the flag has undergone several changes. An act of January 13, 1794 changed the flag to fifteen stripes and fifteen stars; however the act of April 4, 1818 reinstated the thirteen stripes and declared that one star for each state added be incorporated into the flag on the 4th of July following its admission to the union. The next change to the flag did not occur until June 24, 1912 when President Taft established standard proportions for the flag and set the arrangement of the stars in horizontal rows with "a single point of each star to be upward." The final presidential change was issued August 21, 1959 when President Eisenhower set the arrangement of the stars as nine rows of stars staggered horizontally and eleven rows staggered vertically.

The flag of the United States has been an enduring national symbol since January 1776 when George Washington ordered the flag known as the Grand Union flag raised above his base at Prospect Hill. Since that time, the flag has represented America on some truly amazing adventures.

• In 1787 Captain Robert Gray carried the flag around the world on his ship The Columbia.
• During the civil war, although the South seceded from the union, President Lincoln would not allow any stars to be removed.
• In 1909 Robert Peary placed an American flag sewn by his wife atop the North Pole.
• On July 20, 1969, astronaut Neil Armstrong placed the flag on the moon.
• In 2011, just hours after the attack, the photo "Raising the Flag at Ground Zero" is taken to show three New York City firefighters raising the American flag at Ground Zero of the World Trade Center, becoming a national symbol of hope and triumph over adversity.