You wouldn't know it from the upbeat melody, but "Walkin' On The Sun" by Smash Mouth is about the 1992 Los Angeles Riots.
Richard Harris, who played Professor Dumbledore in the first two Harry Potter movies, had a hit in 1968 with "MacArthur Park."
John Legend wrote "All Of Me" about his fiancée Chrissy Teigen. He sang it to her at their wedding ceremony in Como, Italy.
"Here Comes Your Man" is the closest the Pixies came to a hit in America. It was rumored to be about a drug dealer, but Black Francis says it's just a story about some hobos who travel by train and die in an earthquake.
Jay-Z did the rap on Beyoncé's "Crazy In Love" at the last minute. They had just started dating; she asked him to feature on the track the night before she had to turn in her album.
When "Last Friday Night (T.G.I.F.)" climbed to #1 on the Hot 100, Katy Perry became the first woman to send five songs from one album to the top of the charts. The four previous chart-toppers from her Teenage Dream set were "California Gurls," "Teenage Dream," "Firework" and "E.T."
A popular contemporary folk singer, Williams still remembers the sticky note that changed her life in college.
Medley looks back on "Unchained Melody" and "You've Lost That Lovin' Feelin'" - his huge hits from the '60s that were later revived in movies.
"Lullaby" singer Shawn Mullins on "Beautiful Wreck," beating the Devil, and his writing credit on the Zac Brown Band song "Toes."
"London Bridge," "Ring Around the Rosie" and "It's Raining, It's Pouring" are just a few examples of shockingly morbid children's songs.
Tim and his brother Richard are the Furs' foundation; Tim explains how they write and tells the story of "Pretty In Pink."
The country sweetheart opines about the demands of touring and talks about writing songs with her famous father.