Most people have a general idea of the inspiration behind "The Star-Spangled Banner". After a long overnight attack in August of 1814, the following morning the American flag was still flying over Fort McHenry, which guarded the harbor and city of Baltimore. The flag was battered and torn, but it was still flying.

But most people don’t know that Francis Scott Key saw the battle from aboard a British ship that was participating in the attack on the fort. A close friend had been taken prisoner of war by the British and Key along with a U.S. negotiator boarded the ship trying to make a deal for his release. But the attack on the fort began as they were negotiating, so they weren’t allowed to leave the ship.

During the night all he could see was the explosions from the cannonballs being directed at the fort, but he was surprised at what he saw the following morning. The words almost immediately came to his head.

But it was more than a hundred years before the United States adopted the song as the national anthem. It was on this date in 1931 that Congress made "The Star-Spangled Banner" our national anthem – making every March 3 National Anthem Day.