1 of 3 | Denver Broncos defensive tackle Kevin Vickerson carried an American flag onto the field during team introductions to honor the tenth anniversary of the 9-11 attack against the United States at Sports Authority Field at Mile High on September 12, 2011 in Denver. UPI/Gary C. Caskey | License Photo
The poem, which was later set to the tune of an old English song, became the national anthem in 1931.