LONDON — What is "Bohemian Rhapsody" about? Short answer: nobody has a clue.

On the one hand, it's the tale of a man who confesses murder to his mother and ends up on trial, but on another it's a nonsensical melange of Florentine astronomers, Rossini characters and Scaramouches.

Some think it references Freddie Mercury's sexuality; others insist it's about spiritual redemption. Wayne and Garth think it's just good for a head bang.

As one of rock music's most histrionic and memorable tracks hits its 40th birthday (the original was released during a relatively dull period between glam and punk on Oct. 31, 1975), here are 16 things we definitely do know about Queen's masterpiece.