In 1939, a polka craze swept America thanks to "Beer Barrel Polka (Roll Out The Barrel)."

Imagine Dragons lead singer Dan Reynolds says their 2012 hit "Radioactive" is "a song about having an awakening; kind of waking up one day and deciding to do something new, and see life in a fresh way."

Bing Crosby debuted the song "White Christmas" in the 1942 movie Holiday Inn, where he plays a New Yorker stuck in Southern California for Christmas and missing the snow. The song became a Christmas classic and the basis for the 1954 movie White Christmas, also starring Crosby.

Glen Hansard and Marketa Irglova starred in the movie Once, which featured their song "Falling Slowly." Bob Dylan liked the song and movie so much he gave them an opening slot on his tour.

The Phoenix song "1901" is about Paris. Their lead singer Thomas Mars said: "Paris in 1901 was better than it is now. So the song is a fantasy about Paris."

"Instant Karma" is one of John Lennon's most hopeful songs, written and recorded in one day at a time when he felt people were pulling together in a positive direction.
The outlaw country icon talks about the spiritual element of his songwriting and his Bob Dylan mention.
Guitarist Tony Iommi on the "Iron Man" riff, the definitive Black Sabbath song, and how Ozzy and Dio compared as songwriters.
Chris tells the story of "Wicked Game," talks milkshakes and moonpies at Sun Records, and explains why women always get their way.
Phil was a songwriter, producer and voice behind many Philadelphia soul classics. When disco hit, he got an interesting project: The Village People.
It took him seven years to recover from his American hit "Fool (If You Think It's Over)," but Chris Rea became one of the top singer-songwriters in his native UK.
David Gray explains the significance of the word "Babylon," and talks about how songs are a form of active imagination, with lyrics that reveal what's inside us.