The Star-Spangled Banner is the official anthem of the United States. It was written by an amateur poet named Francis Scott Key. The lyrics are actually a part of a poem titled "Defense of Fort McHenry," which was written in 1814 after Key witnessed the bombardment of Fort McHenry by the British. The poem was later set to the tune of the popular British song "To Anacreon in Heaven" by John Stafford Smith.
A congressional resolution to make The Star-Spangled Banner the national anthem was passed on March 3, 1931. The song is notoriously difficult to sing, and features a range of vocal tones that can be difficult to reach. In this video, watch how this crowd unexpectedly comes together to sing America's national anthem.