You've probably heard Gimme Shelter, even if you don't know it by name. It's in practically every Martin Scorsese film, and one of the most popular rock songs of all time.

And you'll have heard the screams of Merry Clayton backing vocals in the song:

This backing vocal turned the song from good to great.

But these lines conceal a dark story. Merry was heavily pregnant at the time of recording. She came into the studio late at night, getting called up past midnight and arriving in her slippers and hair in curlers, and pushed herself so hard recording the vocal, hitting several vocal cracks across several takes to record a truly epic line. But she'd pushed it too far, she returned home and had a miscarriage. It devastated her, and she didn't listen to Gimme Shelter for years after.

To hear the vocal line and her reflecting on the moment, years later, check out this video: Merry Clayton's duet with Mick Jagger on "Gimme Shelter" - YouTube. A hauntingly beautiful story.