Did you know the actual national anthem was made by taking the melody from a popular drinking song "To Anacreon in Heaven", and pairing it with the lyrics of Francis Scott Key?
I never knew that either until today. I thought it was an original composition. It's still patriotic obviously, but this blew my mind.
http://www.astrococktail.com
/anacreon.html
Listen for yourself, it's crazy. It goes literally note for note.