Carly Simon's hit 1972 single You're So Vain starts with one of the best opening lines in pop music: "You walked into the party, like you were walking onto a yacht".
This killer lyric helps set up the pretension and vanity of the subject of the song, as well as Simon's kiss-off tone throughout.
It also ignites a mystery that has endured for 50 years, triggering endless debate, plenty of guessing, and even an auction to buy the answer to the mystery.
