There have been many modifications of the flag, most notably the change in stars over time due to the change in the number of states. The flag is also nicknamed "The Stars and Stripes" and "Old Glory".
A picture of the flag can be seen here above.
The National March of the United States of America is "Stars and Stripes Forever," a popular rendition done by John Phillips Sousa honoring the American Flag. You can listen to the song here:
Throughout history, the US flag has gained additional prominence as a symbol of freedom and democracy in the world, thanks in large part to American involvement in world affairs since the turn of the 20th century.